ABSTRACT BOOK

Third International Conference on

Powder, Granule and Bulk Solids: Innovations and Applications

PGBSIA 2020 February 26-28, 2020

Thapar Institute of Engineering & Technology (TIET),

Punjab-147004, Patiala, India Organized by: Department of Mechanical Engineering, TIET

Third International Conference on Powder, Granule and Bulk Solids: Innovations and Applications

(PGBSIA 2020)

Chair Dr. T. P. Singh, Professor and Head

Department Mechanical Engineering

Organizing Secretary Dr. S. S. Mallick, Associate Professor Department Mechanical Engineering

Co-Organizing Secretary Atul Sharma, Assistant Professor

Dr. Kundan Lal, Assistant Professor Department Mechanical Engineering

February 26-28, 2020

Thapar Institute of Engineering & Technology (TIET),

Punjab-147004, Patiala, India Organized by: Department of Mechanical Engineering, TIET

Message from the Head of Department of Mechanical Engineering and

Conference Chair

It is my pleasure to invite you to attend the Third International Conference on “Powder, Granule and Bulk Solids: Innovations and Applications” on February 26 to 28, 2020 at our TIET campus at Patiala. The Conference will present many papers from a wide range of particle technology aspects. The topics will provide a good balance of theory and practice and we are sure they will be of wide interest to industry and research organizations. This Conference will provide an excellent opportunity for you to meet practitioners, researchers, vendors and designers from many countries around the world and benefit from the presentation of the latest activities in their fields of interest. I express my sincere thanks to the sponsor for supporting this event. I also thank the members of various committees for their effort towards organizing the conference. Dr. T. P. Singh Professor

Message from the Conference Organizing Secretary

I am immensely pleased to welcome you at the Third International Conference on “Powder, Granule and Bulk Solids: Innovations and Applications” (PGBSIA 2020). Particle technology is an interdisciplinary and challenging field of research due to the numerous and complex inter-particle interactions. The conference aims to provide a shared platform to the academic and industry communities to address the challenges, latest developments and share their expertise in different areas of particle technology. Collaborations coming through the conference could foster industry oriented research and developments. The conference is unique in many ways: a strong emphasize is being made for a well proportionate and effective University-Industry participation; India’s potential economy growth presents ample business and research opportunities; high quality papers and presentations and the possibility of getting it published in an International journal of high repute; a significant number of Keynote, Invited Lectures and Workshop sessions delivered by national and international experts from academic and industry communities. I have many people to thank; the list is indeed very long. I sincerely thank all the Keynote Speakers and the Workshop Resource Experts, who have contributed significantly towards making a technical program, which I think is very rich. Sincere thanks go to our sponsor for supporting this event. I thank the patron, advisory committee, technical review committee and the local organizing committee for their support. On behalf of the organizing committee, I once again welcome all of you to PGBSIA 2020. Dr. S.S. Mallick Associate Professor

INDEX

Abstract title Page No.

SESSION: DUST AND AIR POLLUTION 1 Solving industry’s dust problems – a high-tech approach 2 An investigation into utilization of FGD gypsum for GFRG (glass fiber reinforced gypsum) panel manufacturing 3 Dust explosions and venting protection 4 Modelling of dust suppression for the loading of bulk carrier ships 5 Computational prediction of dust suppression efficiency of water spraying systems – a review 7 SESSION: FLOW PROPERTIES 9 Investigation to infer mechanical energy of cohesive powders 10 High and low temperature ring shear testing 11 Powder flow properties at process conditions and the role of interparticle forces 12 Influence of metallic powder characteristics on spreadability, triboelectricity and packing dynamics in additive manufacturing processes 14 Cohesion and its impact on bulk properties and enhancements through surface modification 15 The effect of temperature on the flowability of polymeric powders 16 Shear yield stress measurement of coal ash pastes from modified slump tests 17

SESSION: GRANULAR FLOW 18 Experimental investigation of segregation of granular materials in a simplified model of blast furnace 19

A revised coarse-graining approach for simulation of highly poly-disperse granular flows 20 An experimental study of segregation of non-spherical particles in a vibrated bed system 21 Velocity scaling in the region of orifice influence in the silo discharging under gravity 22 Understanding the micro-meso-macro mechanics of particulate solids: from theory to applications 23 Fabric-conductivity characteristics of cohesive periodic granular Assemblies 24 SESSION: PNEUMATIC TRANSPORT 25 Numerical investigations of cyclone separators with different cylinder-to-cone ratios 26 Experimental study for modification and validation of plug-3 pressure drop model 27 New approach for investigation on slug porosity of plastic pellet conveyed pneumatically 28 Erosive wear of pipe bends in pneumatic conveying systems and wear life prediction 29 Commonly analyzing particle-gas and particle-liquid flows by using Archimedes number 31 SESSION: POWDER PROCESSING 33 Multifarious powder compositions for detecting fingerprints on crime scene evidence 34 New development in process engineering of dispersion of pigment tinters 35 The influence of pigment particles morphological and morphometrical characteristics on polychrome artifacts restoration 36 Detection, identification and classification of asbestos fibers and asbestos containing materials (ACMS) by innovative optical sensing devices 37

Laser sintering of binary mixtures of ceramic powders 39 Role of spreading solution solvent in determining the morphology of PVDF films deposited by Langmuir-Blodgett method 40 Effective preparation of curcumin nanoparticles by stirred media mills 41 Facile immobilization of iron on carbon nanospheres using organometallic-complex for supercapacitor applications 42 Mixing behavior of binary mixtures in a spout-fluid bed: design of experiments approach 43 Multi input system modeling and fractional order control of cutting forces in machining nanocomposites 44 Micro and nano particle composite machining: fractional order control of surface roughness 46 Innovative optical sensing analytical architecture for microplastics detection, identification and classification 47 SESSION: POWDER SIMULATION 49 Numerical simulation of one dimensional consolidation test of montmorillonite/kaolinite mixtures using discrete element method 50 Particle breakage modelling of granular materials in direct shear test using DEM-XFEM 51 Non-linear breakage and insights from DEM–PBM simulations 52

Calibration of DEM for cohesive particles in the SLS powder spreading process 53 Experimental investigation of segregation of non-spherical particles in a fluidized bed solids-mixer 54 Implementation of cohesive DEM to study agglomeration of Nanoparticles 55 Effect of the contact force model on the bulk flow behavior of granular materials in DEM simulations 56 Measurement of the rolling friction of iron ore pellets for usage

in DEM simulation 57 Multi-scale simulation of the pellet rounding in a spheronization process with different friction plates 58 CFD simulation of pressure drop in slurry pipeline for flow of sand water suspension 59 DEM simulation of packing spherical particles in to slender prismatic containers 60 Powder-based simulations for selective laser sintering and selective laser melting 61 Numerical analysis of the drag coefficient of sphere falling in newtonian fluid while surrounded by other spherical particles 62 Design and analysis of a self-dispersing twisted pipe for fast settling suspensions using computational fluid dynamics approach 63 The finer things in life – challenges and advances in powder simulation using the discrete element method 64 Numerical study on mixing mechanism of a ribbon mixer using the DEM 65 DEM-CFD simulation for powder filling in a multi cavity die 66 Next generation DEM technology: crossing new frontiers with rocky DEM 67 On developing particle-fluid coupled heat transfer model at nanoscale 68 On signed distance function based wall boundary model in

the DEM simulation 69

1

DUST AND AIR POLLUTION

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SOLVING INDUSTRY’S DUST PROBLEMS – A HIGH-TECH APPROACH

Peter W. Wypych, Jon M. Roberts and David B. Hastie1

1 Faculty of Engineering, University of Wollongong, Wollongong, N.S.W.

2522, Australia ABSTRACT: Industries that rely on bulk materials handling and processing face significant challenges in the control of dust to meet emission targets, as well as ensuring sustainable operations. This paper initially describes the main existing options available for dust control with some of their features, advantages and disadvantages. It then presents some of the new technologies that are being researched and developed at the University of Wollongong to minimize dust emissions by addressing product dustiness or dustability and also dust generation mechanisms (the root cause of the problem). This paper also focuses on some of the new techniques and innovative technologies that are being developed and implemented to improve the suppression of airborne dust, specifically through the use of new technology that integrates high-energy micro-mist sprays with advanced dynamic modelling/design techniques. Various case studies are presented in the paper (e.g. ROM bins, conveyor transfers, stackers, continuous miners – including cross-wind/ventilation flow effects) to demonstrate the benefits in applying this new technology to the control of dust in industry (e.g. optimising design solution option/s, maximising dust control efficiency, minimising water consumption).

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AN INVESTIGATION INTO UTILIZATION OF FGD GYPSUM FOR GFRG (GLASS FIBER REINFORCED GYPSUM) PANEL

MANUFACTURING

Vinay Kumar1 and Raj Arjun Pandey1

1Project Engineering Department of NTPC Ltd., Delhi 110003, India

ABSTRACT: In order to meet the latest environmental norms on SOx emission, Thermal Power plants are setting up large numbers of limestone based flue gas desulphurization plants. This will lead to production of massive amount of FGD by-product, gypsum from thermal power plant in the range of 18 million tons to 20 million tons per annum. This clearly mandated the need for exploring various options for FGD gypsum utilization. This paper presents results from an investigation into various utilizations of FGD Gypsum and particularly its utilization for Glass Fiber Reinforced Gypsum (GFRG) panel manufacturing. Various options for Gypsum utilizations were explored in this paper and it was found that GFRG panels as one of the most promising area of FGD gypsum utilization which shall provide an alternative to existing conventional wall & roof, used in building & construction. In order to further study the GFRG panel manufacturing, an Expression of Interest (EOI) for setting up GFRG Panel manufacturing in India was floated. Based on the proposal submitted, techno-commercial analysis for setting up GFRG Panel manufacturing plant was done and limitations of the same were studied in addition to study of the functioning of existing GFRG panel manufacturing plant in India. Accordingly, solutions for the limitations of existing manufacturing technologies are being proposed in this paper. In addition to above, commercial viability for setting up the manufacturing plants were also done and projects were found viable at certain locations with some caveats. It is concluded that the utilization of FGD gypsum in GFRG panel manufacturing is not only a lucrative option but also provide us the sustainable use of FGD gypsum, which otherwise will be a menace for Industry if left unutilized.

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DUST EXPLOSIONS AND VENTING PROTECTION

Álvaro Ramírez-Gómez1

1Department of Mechanical, Chemical and Industrial Design Engineering,

Technical University of Madrid, Madrid 28012, Spain ABSTRACT: Dust explosions occur when fine particles are dispersed forming a cloud that react with oxygen in the presence of an ignition source. Preventive measures are usually considered, but if a dust explosion occurs the only way to avoid devastating consequences is to combine them with protection measures; venting is one of the most popular protection measures. In order to ensure reliability using venting, there are still research topics that deserve more attention such as the influence of the type of structure and its slenderness. Lightweight steel structures like silos are specially affected when determining venting areas. This type of structure is not designed to resist the load exerted by a dust explosion inside and in general the cost to protect them is a problem. When the slenderness of the silo is low the cost involved in the protection using venting systems could be affordable. However, when the slenderness is high, the cost can be significant in comparison with the cost of the steel structure to be protected, because of the large venting areas obtained from current standards. In some cases, as for example those silos that store agricultural materials, this is a limitation that cause that still some of them remain unprotected against dust explosions. Furthermore, differences in the determination of the venting area can be found using different standards. Experiments carried out in a modular vessel 18.5 m

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with different slenderness (L/D) open the discussion in this regard. EN 14491 clearly ensured safety, although it appears to oversize the vent areas in some cases. However, the NFPA 68 standard undersized the vent areas for half of the tests, especially for L/D < 2. More efficient methods to determine venting areas in silos are still needed.

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MODELLING OF DUST SUPPRESSION FOR THE LOADING OF BULK CARRIER SHIPS

Liam Andrews1, Jon Roberts1 and Peter Wypych1

1Faculty of Engineering, University of Wollongong, Wollongong, N.S.W.

2522, Australia ABSTRACT: Dust generation has been a major concern for many researchers and engineers involved in industries such as mining, agriculture, power, food processing and other bulk material operations. Dust can create hazards from the inhalation of fine particles into the lungs, contamination of equipment, dust explosions and the negative impact on the wider community environment. An increasing number of ports and

terminals around the world are employing Rotabox technology for the ship loading of metal powders, such as lead and zinc concentrates. The

Rotabox considered in this study is a hydraulic machine that rotates and discharges a container full of 32 tonnes of bulk material into the cargo hold

of bulk carrier ships. Some of the advantages of the Rotabox technology include: handling of sealed containers (just prior to container rotation and discharge); minimised drop height of material and hence, dust generation, during container discharge. However, the risk of dust emissions from the cargo hold during container discharge is still possible, especially under cross-wind conditions. Some attempts have been made at using dust suppression via micro-mist sprays installed around the top of the cargo hold. To assist in the evaluation of the performance of these new micro-mist sprays with the aim of improving dust suppression or capture efficiency, the University of Wollongong pursued a line of investigation, which included the modelling of the material flow and the subsequent dust-laden air flows. Attempts also were made at modelling the effects on cross-wind conditions and predicting possible dust emissions. Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) were coupled together for the simulation of the dust cloud generated from the

Rotabox operation. The results indicate a significant dust cloud height of over 9 metres (with a full cargo hold) for PM10 dust particles. Other

modelling scenarios, such as side-loading of the Rotabox, show the possibility of 7 micron dust travelling up the vertical sides of the cargo hold walls and escaping through the gaps between the spray bars. Separate CFD simulations were used to investigate the cross-wind effects with the cloud-

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based CFD software SimScale. The steady-state solution results indicate possible dust liberation from the cargo hold due to the relatively high wind velocities generated inside the cargo hold and also due to the relatively high negative static gauge pressures generated by the cross-wind conditions. The results from this research demonstrate the dust generation

mechanism of the Rotabox operation under different conditions and also recommend options to improve the performance of the dust suppression system, such as optimisation of spray bar design and orientation and the installation of deflector plates at strategic locations to minimise dust-laden air escaping between the spray bars.

7

COMPUTATIONAL PREDICTION OF DUST SUPPRESSION EFFICIENCY OF WATER SPRAYING SYSTEMS – A REVIEW

Rongfu Liao1, Peter W. Wypych1, Jon M. Roberts1, Renhu

Pan2

1 International Solids Handling Research Institute, University of

Wollongong, Northfields Avenue, Wollongong N.S.W. 2522, Australia 2Fujian Longking Co., Ltd., Longyan Fujian, 364000 China

ABSTRACT: Dust emissions are very common in the industries that rely on bulk materials handling, from mines and port terminals and also within plants and factories. They can affect production, cause material waste and especially threaten human health. For more than 100 years, people have been working to develop effective methods and systems to suppress dust emissions. Water spraying is one of the oldest and most popular methods for suppressing dust emissions and is still widely used today in many handling and processing operations, such as crushing, transferring, dumping, unloading, etc. However, reports from industry show that a large proportion of spraying dust suppression systems do not work very well, and the most typical problem is that the actual dust suppression efficiency of a spraying system is either not known or does not reach its design value. Also, the users are not willing to maintain the systems and eventually the spraying systems are turned off or even abandoned. The main causes of this problem include: apparent simplicity of water spraying technology; lack of understanding of the dust emission mechanisms; inadequate or improper design resources; improper selection/design of the spraying system components. The risk of spraying system failure can obviously be minimized if its dust suppression efficiency can be predicted accurately for a given problem via a bench-scale test rig and/or through mathematical modelling or computational methods during the design stage. The aim of this paper is to review previous research on predicting dust suppression efficiency of spraying systems mainly via the computational approach. To help better understand the importance of predicting dust suppression efficiency, the mechanisms involved with spraying-type dust suppression systems and some of the other approaches of predicting dust suppression efficiency, such as experimental approach and mathematical modelling, are also reviewed briefly. Finally, the advantages and disadvantages of the outcomes of previous dust suppression efficiency predicting methods are

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concluded and some suggestions on developing an engineering-based method are also provided.

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FLOW PROPERTIES

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INVESTIGATION TO INFER MECHANICAL ENERGY OF COHESIVE POWDERS

Vivek Garg 1, Robert Berry1, Michael Bradley1

1The Wolfson Centre for Bulk Solids Handling Technology, University of

Greenwich, UK ABSTRACT: Surface energy plays a crucial role in determining the cohesive/adhesive behaviour of powder. There are still many challenges in understanding and quantifying the properties of particles and their surfaces that influence the behavior of a bulk assembly of particles (e.g. flowability and kinematics of powders). This paper describes a novel drop test technique for measuring the forces between particles and surfaces with cohesive powders, and then from these inferring an energy value for pulling the particles off the surface, a “mechanical surface energy”. The investigation was undertaken with a wide range of cohesive powders that varied by particle size range and chemistry. This mechanical surface energy was compared against an established inverse-gas chromatography (IGC) technique that determines the dispersive surface energy of the powders. Three existing models (JKR, Rabinovich, Israelachvili) from the literature were selected to study the relationship between surface energy and adhesion force in cohesive powders. The IGC experiments showed that the dispersive surface energy of the powders does not change with particle size, as expected. The above models are also built on the principles that surface energy will not change with particle size, however when applying these models to the drop test results, they suggest that the inferred mechanical energy changes with the particle size range. There is clearly a need to study the contact behaviour of particles in order to modify these models to overcome this divergence. Furthermore, an initial attempt has been made to establish the relationship between mechanical and dispersive surface energy of the powders. The suggestion from this work is that to obtain better contact laws mainly requires better understanding of the effects of surface texture and asperity radius.

11

HIGH AND LOW TEMPERATURE RING SHEAR TESTING

Denis Schütz1 and Timothy Aschl1

1Rheology, Anton Paar GmbH, Anton Paar Strasse 20;8054 Graz, Austria

ABSTRACT: While the behaviour and mechanical coefficients of solids under the influence of temperature is well understood, how this translates to their behaviour when in the form of particulates is not studied in great depth. In this Study we will show both cryogenic as well as high temperature measurements exploring the different ways that temperature influences the behaviour of bulk solids using dedicated measurement equipment. From the onset of melt behaviour in partially crystalline polymers like Polyamide to the effect of the freezing of surface water in flour and other biological samples, the embrittlement of resins at low temperatures to the effect of settling surface water from the atmosphere in cement. All of these effects have their distinct signatures upon the flow behaviour and of course play a major role in their caking behaviour. Both the data, their influence upon silo and hopper design as well as interpretations of the underlying mechanisms will be shown.

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POWDER FLOW PROPERTIES AT PROCESS CONDITIONS AND THE ROLE OF INTERPARTICLE FORCES

Massimo Poletto1

1Department of Industrial engineering, University of Salerno - Via

Giovanni Paolo II, 132 - 84084 Fisciano (SA) – Italy

ABSTRACT: Powder cohesion may have a relevant role in several industrial process operations involving particulate materials, such as fluidization, granulation and drying, as well as storage and solids handling units. Several of these operations require process conditions, which involve high temperatures that, in turn, may affect and change powder cohesion with respect to the ambient. In fact, cohesion in powder is related to the intensity of interparticle forces such as van der Waals, capillary and electrostatic forces and the system temperature can affect all these forces by changing particle hardness, producing liquid capillary phases or modifying the particle dielectric properties. It is of interest, therefore, to have the possibility to measure powder cohesion at the process temperature and to observe possible changes due to temperature changes. Several different characterization tests are available or have been developed to measure powder cohesion. Although powder shear testing had been developed purposely for the design of bulk solids handling units, among the other similar techniques, it has the great advantage of measuring well established physical properties and of being able to produce highly repeatable results. At the University of Salerno, the cell of a Schulze annular shear tester was redesigned and built in order to carry out shear tests at temperature up to 500°C. The High Temperature Annular Shear Cell (HT-ASC) apparatus was used in different collaboration with UCL, East China University of Science and Technology and INSA Lyon to measure the powder flow properties at ambient and high temperatures on ceramic powders and polymer powders uniquely affected by van der Walls cohesive forces as well as with particulates bearing low temperature melting phases and for which the experimental results clearly indicated the presence of capillary forces. Shear tests with the HT-ASC, however, produce results in conditions of powder compaction and flow conditions that might eb relevant for powder handling and silo discharge, but are not necessarily relevant to other processes such as, for example, the reaction in fluidized beds or the spreading step in Selective Laser Sintering. It is necessary, therefore, to analyse the results in order to separate the effect

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of binary interparticle forces from the powder compaction which affect both the intensity of the binary forces and the active number of contacts of the powder. For this reason, shear test results were used to extrapolate the tensile strength of the compacted powders that, in turn, with the help of the Rumpf equation, allowed estimating interparticle forces at the different process temperatures and for the different materials tested. Some of the models available in the literature to describe interparticle forces and their dependence upon powder consolidation were used to understand and verify both the effect of temperature on the powder flowability, and the reliability of the approaches proposed.

14

INFLUENCE OF METALLIC POWDER CHARACTERISTICS ON SPREADABILITY, TRIBOELECTRICITY AND PACKING

DYNAMICS IN ADDITIVE MANUFACTURING PROCESSES

Naveen Mani Tripathi1, Filip Francqui1, and Geoffroy Lumay2

1GanuTools, Rue Jean-Lambert Defrene, 4340, Awans, Belgium

2University of Liège, Allée du 6 Aout, 4000, Liège, Belgium

ABSTRACT: Granular and fine material powders are widely used in many industries such as 3D printing, sintering, alloys etc. To control and optimize processing methods, these materials must be precisely characterized. In this research AlSi10Mg (aluminium alloy with three difference particle sizes and shapes), AlSi7Mg3/5 (standard aluminium alloy) and a Scalmalloy (an aluminium alloy with high mechanical resistance) are tested for spreadability and electrostatic charge investigation, and two steel powders are tested for packing dynamics investigation. The GranuDrum, GranuPack, and GranuCharge instruments are utilized for these investigations. These parameters are very important for the additive manufacturing industries. AlSi10Mg powder with smallest particle size is found to have least spreadable and TiAl6V4 has lowest cohesive index that means best spreadability. GranuCharge instrument confirms that net change in the charge of AlSi10Mg powder with smallest particle size is least after flowing through the SS316L pipe, this phenomenon confirms that powders starts to form agglomerates during flow. AlSi10Mg powder with medium particle size attains highest net change in electrostatic charge this confirms that tendency to attain the charge during flow is highest for this particular particle size range. Our moto to select three different particle size of a powder is to confirm that there should be a balance in the particle size fineness, spreadability, and flowability. Packing dynamics is a quasi-static process and a series of experiments were performed utilizing the two steel powders. It was found that carpenter steel powder has better packing dynamics than the LPW powder.

15

COHESION AND ITS IMPACT ON BULK PROPERTIES AND ENHANCEMENTS THROUGH SURFACE MODIFICATION

Rajesh N. Davé1

1New Jersey Center for Engineered Particulates, New Jersey Institute of

Technology, Newark, NJ, USA ABSTRACT: Fine powders are increasingly popular in various industry sectors for a variety of reasons. In general, the reason for not being able to utilize fine powders appears to be their high cohesive relative to the gravitational and other process-based forces. High cohesion leads to poor flow, packing fraction or bulk density, poor dispersibility, lack of fluidizability, formation of agglomerates, etc., which all adversely impact downstream processing and final product quality and prevent wider-scale use. A typical dimensionless parameter of consideration is the granular Bond number, which is a ratio of inter-particle adhesive forces and body forces. In dry state, the adhesive forces are predominantly those from van der Waals interactions. Although this parameter has been used frequently in literature, its estimation remains a challenge. In this talk, using examples from pharmaceutical industry, the impact of cohesion on various keep properties will be discussed, followed by contact models that help estimate the Bond number. Typically, smaller Bond number implies better flow, fluidization, dispersion, etc. Next, various means for reducing the Bond number are considered and most effective approach, namely surface modification, is discussed. The rationale behind surface modification and practical means to do that are considered next. Results of bulk property enhancements are presented along with proposed phase maps that allow easier discernment of the extent of enhancements and to justify the need for surface modification. The results for pharmaceutical blends are presented both in case where the excipients are surface modified and when the drug powders are surface modified, presenting pathways for determining the need for engineered excipients. This brings out a major question of predicting bulk powder properties from particle-scale followed by properties of mixtures. Our current work in that area is also presented.

16

THE EFFECT OF TEMPERATURE ON THE FLOWABILITY OF POLYMERIC POWDERS

Sina Zinatlou Ajabshir1, Diego Barletta and Massimo Poletto

1Department of Industrial Engineering, University of Salerno – I-84084

Fisciano (SA) - Italy ABSTRACT: Several studies in the recent literature proved that temperature can significantly affect the flowability of powders by changing the intensity of cohesive interparticle forces like van der Waals forces and capillary forces. This effect is relevant to a variety of industrial processes involving dense powder flow. Among these, one of the most recent applications is the Selective Laser Sintering (SLS) of powders. In this work, the effect of temperature on polymeric powders is studied by shear testing with the High Temperature Annular Shear Cell (HT-ASC) for the Schulze Ring Shear Tester and the new Anton Paar Shear Cell. In particular, yield loci were obtained from ambient temperature to values approaching the melting point of polymeric particles. Measurements results were analyzed to separately assess the effect of temperature on friction, cohesion and unconfined yield strength at different consolidation conditions. Measurements results obtained by means of the two shear cells were consistent. In particular, it was found out that revealed that the flowability of the powders significantly get worse as the temperature approach the polymer melting point. The relevance of these results for applications was highlighted by calculating the granular Bond number, as the ratio between the interparticle force, estimated from measured bulk flow properties, and the particle weight due to gravity.

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SHEAR YIELD STRESS MEASUREMENT OF COAL ASH PASTES FROM MODIFIED SLUMP TESTS

Vighnesh Prasad1, Surya P. Mehrotra2, and Prachi Thareja1

1Department of Chemical Engineering, Indian Institute of Technology,

Gandhinagar, 382355, India 1Department of Material Science & Engineering, Indian Institute of

Technology, Gandhinagar, 382355, India ABSTRACT: The hydraulic transportation of coal ash slurry through pipelines is a cost-efficient, safe and environment-friendly option for handling, utilization and disposal of a large amount of coal ash. During transportation through pipelines, the shear yield stress plays a vital role in dictating the flowability and pumping energy required to transport the slurries. In the present investigation, coal ash with two different particle sizes is chosen to prepare a coal ash paste by adding 72-76 wt% of particles in tap water. Shear yield stress is measured from slump tests, and the results are further compared with the widely accepted Vane test. We propose a new modified slump test with a cubical geometry to estimate the yield stress of coal ash paste. The limitations of the currently used mini cone and cylinder slump models are addressed, and in the modified slump test with the cubical geometry, a new theoretical relationship between slump height and yield stress is proposed. Our results demonstrate that the yield stress determined from cubical slump test is the closest to the vane test results. On the other hand, due to the violation of model assumption, presence of air pockets and improper filling of slump geometries, both the cone and cylinder slump tests show the significant deviation to the vane test results. Our results also indicate that the yield stress increases exponentially with coal ash loading and decreases exponentially with the incorporation of coarse coal ash particles in pastes. We suggest that the coarse particles present in the thick coal ash paste can reduce the energy required to pump the pastes in the pipeline. Moreover, the slump test with cube geometry appears to be a better alternative to the existing slump models.

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GRANULAR FLOW

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EXPERIMENTAL INVESTIGATION OF SEGREGATION OF GRANULAR MATERIALS IN A SIMPLIFIED MODEL OF BLAST

FURNACE

Sandip H. Gharat1, Nilesh P. Badgujar2 and Shyam P. Tekade3

1Department of Chemical Engineering, Shroff S. R. Institute of Chemical

Technology Ankleshwar, Gujarat 393 135, India 2Department of Chemical Technology, Shroff S. R. Institute of Chemical

Technology Ankleshwar, Gujarat 393 135, India 3Deparmtent of Chemical Engineering, Gharda Institute of Technology

Lavel - Ratnagiri, 415708, India ABSTRACT: Granular materials are the second largest materials available in industry after water. They segregate during surface flow due to differences in size, shape and density. In this paper segregation of different sized particles of equal density is studied to understand the dependence of volume of pouring, weight fraction in the mixture, and variation in height (h) of the divider from bottom. Binary mixture of a specified composition is poured intermittently into the auxiliary hopper and then allowed to pass through the gap (k=5mm) between the divider and the plate and finally settle on to the heap. Experiments were carried using stainless steel (SS316) balls of different sizes (1, 1.5, and 2mm) as model granular materials. The images taken are analyzed using computer code to detect the particles. Image analysis technique is used to detect the position and size of the particles. Profiles of number fraction of big (2 mm) particles vs component x (mm) with depth y (mm) in the layers are plotted separately for top and bottom part of heap. Results shows that larger particle travel more distance while small particles deposited near the pouring end. Variation in surface layer is also observed for each case studied. During each pouring, particles deposited on top of the surface gets eroded by fresh pouring and form new surface profile.

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A REVISED COARSE-GRAINING APPROACH FOR SIMULATION OF HIGHLY POLY-DISPERSE GRANULAR FLOWS

Suranita Kanjilal1 and Simon Schneiderbauer2

1&2

Department of Particulate Flow Modelling, Christian Doppler Laboratory for Multi-Scale Modelling of Multiphase Processes, Johannes

Kepler Universität, Linz, Austria ABSTRACT: The discrete element method (DEM) is widely used to model granular flow systems. It is, therefore, an important simulation tool for many industrial applications. However, this method is computationally expensive for a large number of particles. Hence, an alternative method is required. To model mixing and transport of lumpy materials during the filling of hoppers, a hybrid method has been applied to simulate poly disperse hopper flow. Here, larger particles are resolved by using DEM and smaller particles are represented by a coarse-grained parcel approach in order to reduce computational cost. Initially, spherical particles are chosen for the simulation. However, the parcel approach does not reveal the correct particle segregation dynamics through the densely packed particle bed since the small particles are replaced by larger parcels. This can be explained by the incorrect percolation of the parcels representing the small particle size fraction through the bed of large particles. Therefore, we have implemented a revised coarse-graining approach using a corrected diameter for the collisions of parcel containing small particles and the large DEM particles. The results are quantified with a reference DEM solution in terms of volume fraction. This comparison is executed in a two-step process: 1) simulation of dynamics of particles when they are allowed to fall under gravity through a packed particle bed and 2) hopper flow simulation. We show how the effect of size ratio and coarse grain ratio together play role in this quantification process. Finally, the results show fairly good agreement of the revised coarse-graining approach with the reference DEM simulations.

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AN EXPERIMENTAL STUDY OF SEGREGATION OF NON-SPHERICAL PARTICLES IN A VIBRATED BED SYSTEM

Jeetram Yogi1, Sanjay Verma2, Sunil2 and Anshu Anand2

1Department of Chemical Engineering, Indian Institute of Technology,

Roorkee 247667, India 2Department of Chemical Engineering, Indian Institute of Technology,

Roorkee 247667, India ABSTRACT: The effect of granular particles properties (such as shape), various system parameters (such as frequency), bed geometry and fill height etc. for uniform mixing process is studied experimentally along vertical axial direction in vibrating system, using four varieties of non-spherical particles with different aspect ratios and three different sizes of spherical particles. To explore the effect of non-spherical particles on segregation in many unit operations such as those employed in chemical, pharmaceutical and food industries. The present work shows that segregation is dependent on both the shape of the particle (ellipsoids, cube, and elongated needle) and vibration parameters (amplitude and frequency). The study was carried out by fixing one of the particles of a binary mixture to be a sphere and varying the shape of the other particle. The outcomes indicate that the value of normalized segregation index (SI) was significantly decreased by increasing the degree of elongation of coarse particles. Furthermore, some aspects of a binary particle mixing is significantly affected by vibration parameters, density of coarse particle and differ the filling mass ratio. The results indicate that increasing the amplitude or frequency, the value of SI decreases in the vertical vibrating system for binary granular mixtures. These results have relevant industrial design implications and provide important heuristic to reduce segregation by selecting the shape of the particles and optimal vibration parameters.

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VELOCITY SCALING IN THE REGION OF ORIFICE INFLUENCE IN THE SILO DISCHARGING UNDER GRAVITY

Ashish Bhateja1

1School of Mechanical Sciences, Indian Institute of Technology Goa,

Ponda 403401, Goa, India ABSTRACT: The flow field in the silo discharge varies significantly as grains approach the outlet. It is known that the velocity of grains within the outlet scales with square root of the outlet size. However, there is no such scaling observed as we move upstream of the flow. This study utilizes soft-particle discrete element computations to examine velocity scaling in the region of orifice influence, i.e., the region located in proximity to the outlet of the silo. In particular, we explore the existence of a length scale capable of scaling the velocity of grains, when considered with reference to the velocity at the outlet, in the region of orifice influence.

23

UNDERSTANDING THE MICRO-MESO-MACRO MECHANICS OF PARTICULATE SOLIDS: FROM THEORY TO APPLICATIONS

Stefan Luding1

MultiScale Mechanics (MSM), Department Thermal and Fluid Engineering (TFE), Faculty of Engineering Technology (ET), MESA+, POBox 217, 7500

AE Enschede, Netherlands Email: s.luding@utwente.nl; Website:

http://www2.msm.ctw.utwente.nl/sluding/ ABSTRACT: The behavior of particles such as powders and granular matter – like sand, cohesive powders, suspended particles, colloids or macro-molecules – is of considerable interest in a wide range of industries. These materials are intrinsically dissipative and disordered; often they come with a wide distribution of particle sizes and materials/mixtures, and can behave both solid- or fluid-like. The related mechanisms/processes in particle systems are active at multiple scales (from nanometers to meters) and understanding them is an essential challenge for both science and application. In order to understand the fundamental micro-mechanics one can use particle simulation methods, where often the fluid between the particles is important too, but neglected here. However, large-scale flow applications (due to their enormous particle numbers) have to be addressed by coarse-grained models or by rheology or continuum theory. In order to bridge the gap between the scales, so-called micro-macro transition methods are necessary, which translate particle positions, velocities and forces into density-, stress-, and strain-fields. These macroscopic quantities must be compatible with the conservation equations for mass and momentum of continuum theory. Furthermore, on the intermediate scale of the microstructure (fabric) non-classical fields are needed to describe the micro-structure or the statistical fluctuations, e.g. of the kinetic energy, before one can reach the ultimate goal of solving large industrial application problems.

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FABRIC-CONDUCTIVITY CHARACTERISTICS OF COHESIVE PERIODIC GRANULAR ASSEMBLIES

Akhil Vijayan1 and Ratna Kumar Annabattula1

1Mechanics of Material Laboratory, Department of Mechanical

Engineering, Indian Institute of Technology, Madras, Chennai-600036, Tamil Nadu, India.

ABSTRACT: Granular assemblies are a cluster of discrete particles found around us in many forms such as a sand piles, pulses and food grains. Understanding the influence of particle-particle interactions on the macroscopic phenomena like heat and force transfer has several implications for the design of engineering systems comprising granules. In a granular assembly, the contact network formed by all the contact normals at the particle contacts is referred to as fabric. The fabric of a granular assembly significantly influences its macroscopic response. The inter-particle contact that describes the fabric of a granular assembly strongly influences its thermal/electrical conductivity. In the present work, a generalized tensorial form, linking the fabric and the conductivity, deduced from the works of is presented. The model is found to be consistent with the formulations present in the literature. This form is further used to compare the effects of the presence of cohesive forces between particles onto the behavior of granular assemblies. During shearing of granular assemblies, contact mechanisms like contact creation, contact disruption, and contact reorientation take place. Under the influence of cohesive forces, a tremendous change in their behavior in terms of these mechanisms is expected. Hence, the present work also investigates the effect of cohesive forces on the evolution of the contact mechanisms. Tracking of particle movements during shearing of the periodic granular cell is done using Discrete Element Method. It is observed that the evolution of contact anisotropy and average coordination number for assemblies with the particles of different friction. At higher strain, the effect of particle friction overcomes the cohesive energy displaying a diverging trend. Results also reveal a strong influence of cohesive forces on the evolution of contact propagation during shear thus influencing the effective conductivity of the assembly.

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PNEUMATIC TRANSPORT

26

NUMERICAL INVESTIGATIONS OF CYCLONE SEPARATORS WITH DIFFERENT CYLINDER-TO-CONE RATIOS

Ravi Shastri1, R.P. Sharma1, Lakhbir Singh Brar1*

1Mechanical Engineering Department, Birla Institute of Technology,

Mesra, Ranchi 835215, India *Corresponding author. Tel.: +91-9431115088; fax: +91-651-2275401

E-mail address: brarlsb@gmail.com, brarls@bitmesra.ac.in ABSTRACT: The objective of this paper is to evaluate numerically the effect of changing length of cylinder and cone in a way that the total cyclone length remains unaltered. For this purpose, five different cyclone models with increasing cylindrical lengths (Hc/D = 0.5, 1.0, 1.5, 2.0, and 2.5) have been considered. Comparison is made among various flow variables and performance parameters. Unlike general engineering flows, cyclonic flows possess strong swirl; resulting in high streamlined curvatures and rapid changes in strains, which makes it anisotropic in nature. Body fitted hexahedral mesh is generated using multi-block unstructured technique to fill the entire cyclone domain. The Navier-Stokes equations are discretised using finite volume methods and are iteratively solved using commercially available CFD code FLUENT 6.3.26. Reynolds stress model (RSM) has been used as a closure model for Reynolds-averaged Navier-Stokes (RANS) equation, which solves transport equations for the Reynolds stresses together with an equation for the dissipation rate. Collection efficiency, pressure drop and tangential velocity is found maximum for cyclone with ratio Hc/D=0.5 and minimum for Hc/D=2.5. It has also been observed that at higher inlet velocities, heavier dust particles accumulate near the cyclone roof which may result in high rates of wall erosion.

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EXPERIMENTAL STUDY FOR MODIFICATION AND VALIDATION OF PLUG-3 PRESSURE DROP MODEL

Anubhav Rawat1,2 #, Haim Kalman2, 3

1Motilal Nehru National Institute of Technology-Allahabad, Pryagraj-

211004, UP, India 2Laboratory for conveying and handling of particulate solids, Department

of Mechanical 3

Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheba 84105, Israel

3Aron Fish Chair in Mechanical Engineering-Fracture Mechanics

#anubhav_1982@yahoo.com, Anubhav-r@mnnit.ac.in

ABSTRACT: For the plug flow mode of dense-phase pneumatic conveying, three different classical types of plugs have been defined, and models for predicting the pressure drop in conveying pipeline have been established. In literature, the model for Plug-3 pressure drop is mechanistic and depends on several properties of the materials forming the plug and the plug structure. Therefore, modification of the model with experimentally corrected properties is considered in this study. Laboratory experiments are conducted in 2”,3” and 4” pipelines at low air superficial velocities at which Plug-3 exists. The experiments are conducted on 5 different particulate materials having Archimedes number in the range of 10

2 to 10

4.

Using the new functional relationships, the Plug-3 pressure drop model is modified and its predictions are compared with experimentally measured pressure drops obtained in conveying Plug-3. It is found that the modified Plug-3 pressure drop model matches experimental values reasonably well.

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NEW APPROACH FOR INVESTIGATION ON SLUG POROSITY OF PLASTIC PELLET CONVEYED PNEUMATICALLY

Yassin Alkassar1, O. Orozovic2, Vijay K. Agarwal1, R. K.

Pandey3, Niranjana Behera4

1Centre for Automotive Research and Tribology (former ITMMEC), Indian

Institute of Technology, Delhi, New Delhi-110016, India. 2Centre for Bulk Solids and Particulate Technologies, School of

Engineering, University of Newcastle, 2308, Australia. 3Department of Mechanical Engineering, Indian Institute of Technology,

Delhi, New Delhi-110016, India. 4School of Mechanical Engineering (SMEC), VIT University, Vellore-

632014, India.

Abstract: The objective of this paper is to report the mathematical findings related to the inner structure of slugs (i.e. porosity) that flow in dense phase pneumatic conveying pipeline system. Investigations have also been carried out to study the effect of slug position along downstream of flow on slug porosity. In experiments, plastic pellet having 4 mm particle diameters used as conveyed material, was transported in slug mode flow through 17 m long pipeline of 83.5 mm diameter. The horizontal pipeline was incorporated with two Perspex sections at different locations along the pipeline that allow revealing the behavior of slugs at various locations. For mathematical models, experimental pressure drop and slug velocity with a combination of the Ergun model have been utilized for studying slugs porosity. The substantial variation in predicted slug porosity has been revealed from Ergun model which lead to a new approach based on continuity and momentum equations. The new model reveals constant trends in slug porosity with irrespective of slug positions or operating parameters that are consistent with physical meanings of flow.

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EROSIVE WEAR OF PIPE BENDS IN PNEUMATIC CONVEYING SYSTEMS AND WEAR LIFE PREDICTION

T. Deng1*, M.S.A. Bradley

1The Wolfson Centre for Bulk Solids Handling Technology, University of

Greenwich, UK

ABSTRACT: Pneumatic conveying is widely used around the world by many industries. It provides an effective means of transporting material through plant without the need for transfer points at changes of direction (as would be needed for mechanical transport) with their associated dust generation and mechanical complexity, and it provides excellent isolation between the conveyed material and the surrounding environment. One drawback to the transport of particulates in a gas suspension is that if the particles are hard and angular, then erosive wear (and eventual penetration of the pipe wall) can be a major issue. Pneumatic conveyor bends can be susceptible to a high level of erosive damage under certain circumstances, which can lead to unplanned shutdowns of the plant if pipe wall puncture occurs, as well as dust emission and associated hazards. The importance of predicting penetration rate, to allow management of the replacement of pneumatic conveying bends, is clear, and research into bend failure on pneumatic conveyors has been undertaken at the Wolfson Centre for nearly 30 years. A centrifugal type of erosion test facility has been developed, which can provide closely controlled test conditions of particle impact velocity and angle to simulate the conditions in a pneumatic conveyor bend. Based on the specific erosion rate obtained by the tester for the bend material and a numerical model developed at the Wolfson Centre, the bend life for the anticipated conditions can be predicted. As well as enabling planned maintenance, this can be used for assessing bend life improvement by using different bend materials, and making economic comparisons between different bend materials. A case study of wear resistant materials used for on conveying fans in a pneumatic pulverised sewage sludge handling system is given, which shows the practical wear problems for industry and solution finding in term of wear erosive rates for prediction of bend life. The work at the Wolfson Centre has shown that erosive wear of pneumatic conveyor bends can result in serious costs and cause substantial risks on operations of the systems, but that it can be predicted to a useful level of accuracy based on the characterisation of the erosiveness of the conveyed material using the

30

small scale tester erosion tester. This information can be used to select bend materials, minimising the risks of unplanned maintenance and spillage.

31

COMMONLY ANALYZING PARTICLE-GAS AND PARTICLE-LIQUID FLOWS BY USING ARCHIMEDES NUMBER

Haim Kalman1

Aaron Fish Chair in Mechanical Engineering – Fracture Mechanics

Laboratory for Conveying and Handling of Particulate Solids (CHoPS-Lab) Department of Mechanical Engineering, Ben-Gurion University of the

Negev, Beer-Sheva, Israel hkalman@bgu.ac.il

ABSTRACT: When particles are conveyed in a horizontal pipe, they are moving both horizontally (axially) and vertically (radially). The horizontal flow is dominated by the inertia of the fluid and the drag force (opposing movement). Therefore, in most models for two-phase flow, the Reynolds number obviously plays a major role. The vertical movement of the particles is basically affected by the particle weight, buoyancy force, and drag or viscous force. It is common to analyze Pneumatic Conveying (PC) systems using the Froude number (Fr), which is defined as the ratio between the inertial force and the particle weight. However, the Fr number takes into account the particle weight and neglects the buoyancy force. Although this simplification might be valid for PC, it is firstly not correct and certainly not valid for Hydraulic Conveying (HC). Hence, some recent works on various threshold velocities (mainly for PC, but in some cases, also including HC) showed that the Archimedes number (Ar) is more appropriate. Later, by considering the various forces affecting some threshold velocities, it was confirmed that the Re and Ar affect the velocities for both PC and HC. The Ar is defined in the same way as the Re (encouraging force divided by the resisting force) but for the vertical movement, i.e., as the ratio between the sinking force (weight minus buoyancy) and the viscous force. Since, in PC, the air density in most cases is negligible compared to the particle density, there should not be a difference between the particle weight and sinking force. However, when one is interested in including both PC and HC in a common analysis, the Ar must be used. A number of cases will be presented to show the power of Ar to analyze various materials in either PC or HC. Some threshold velocities are defined for more than 50 materials in both gas and liquid by using Ar number. In addition, Ar number was also successfully used to define steady-state particle velocity for a few materials in horizontal pipes

32

of both PC and HC. Finally, the use of Ar number enabled to develop a flow regime chart for PC including all types of two-phase flow.

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POWDER PROCESSING

34

MULTIFARIOUS POWDER COMPOSITIONS FOR DETECTING FINGERPRINTS ON CRIME SCENE EVIDENCE

Gurvinder S. Sodhi1 and Jasjeet Kaur2

1Forensic Science Unit, S.G.T.B. Khalsa College, University of Delhi, Delhi-

110007; E-mail:sodhigs1@rediffmail.com 2Department of Chemistry, Shaheed Rajguru College of Applied Sciences for Women (University of Delhi), Vasundhara Enclave, Delhi-110096; E-

mail: kjasjeet@hotmail.com ABSTRACT: It may be claimed that there is no more effective deterrent to crime than the certainty of detection. Equally true is that there is no surer way of establishing identity than by fingerprints. The detection of fingerprints at the scene of crime is therefore one of the most powerful tools available in casework investigations. Criminal offenders tread carefully and try not to leave any evidence at the site of crime. They may do so by spraying water on the physical evidence or by setting the entire crime scene afire. This communication reports the utility of novel, fluorescent powder compositions which can develop fingerprints on unique, difficult and unconventional crime scene evidence. These can also lift fingerprints from arson sites. Moreover, these can detect fingermarks on those crime scene exhibits that have been deliberately or accidently wetted. The compositions are non-toxic, indigenous and suitable to work under Indian conditions. The technique requires neither a sophisticated instrument nor costly equipment. It may be operated even by an amateurish hand.

35

NEW DEVELOPMENT IN PROCESS ENGINEERING OF DISPERSION OF PIGMENT TINTERS

Nilesh P. Badgujar1, Sandip H. Gharat2, Ravindra D. Kulkarni3

1Department of Chemical Technology, Shroff S. R. Institute of Chemical

Technology Ankleshwar, Gujarat 393135, India 2Department of Chemical Engineering, Shroff S. R. Institute of Chemical

Technology Ankleshwar, Gujarat 393135, India 3Department of Oil, Oleo-chemicals and Surfactants Technology, Institute

of Chemical Technology Matunga, Mumbai 400019 -India ABSTRACT: Today’s commercial challenge with using pigments is achieving a stable, fine-particle pigment dispersion. This is especially the case for aqueous pigment dispersions. Thus, it is desirable that a dispersant is optimized to effectively wet, disperse and stabilize pigments during the milling process. There are two commonly used ways of incorporating insoluble dry pigments in liquid coatings, viz., direct pigment grinding and the use of pigment concentrates (tints). The use of resin-free pigment tints (slurries), high levels of pigment wetting and dispersing additives are used in direct grinding method the dispersion of pigment in suitable polymeric resin which acts as a stabilizing agent which form protective layer over the de-agglomerated primary pigment particle. It is time consuming process and uneconomical during the making of small batches of multiple colours also do not provide protection against flocculation due to the polymeric resin having low affinity towards pigment. The various pigments employed. The dispersion of pigment in water based systems with surfactants has been investigated using a high speed disperser and bead mill (Interchangeable Dispermat System). Experiments were carried out to understand the effect of mill speed and type of surfactants on the extent of de-agglomeration and the colour strength. The experimental result will be monitored by colour strength analysis, particle size distribution and also confirmed it by different laboratory analysis.

36

THE İNFLUENCE OF PİGMENT PARTİCLES MORPHOLOGİCAL AND MORPHOMETRİCAL CHARACTERİSTİCS ON

POLYCHROME ARTİFACTS RESTORATİON

1Giorgia Agresti, 2*Giuseppe Bonifazi, 2Giuseppe Capobianco, 1Claudia Pelosi, 2Silvia Serranti

1Department of Economics, Engineering, Society and Business

Organization, University of Tuscia, Viterbo, Italy 1Department of Chemical Engineering Materials Environment,

Sapienza University of Rome, Italy *contacting author: giuseppe.bonifazi@uniroma1.it

ABSTRACT: The particle size of painting pigments is relevant for the final colour of the painted areas and also for the conservation and restoration of polychrome artefacts in terms of its role in colour changes. The knowledge of the optical characteristics of pigments used by artists and suppliers in earlier times represents an important starting point for the study and characterization of paintings. The optical properties of a pigment and in particular the hiding power, the tinting strength, and the colour depend on the dimensions and form of its grains. In this study a selected group of pigments were chosen for investigating the particle size and its influence on colour, in particular yellow pigments based on lead, tin and antimony produced and used since ancient times according to different recipes. Previous studies showed that different pigments were produced by varying temperatures, times of firing, molar ratios of the reagents, kinds of crucible, addition of melts and salts. In order to evaluate the influence of particle size distribution on colour characteristics, starting from our previous studies, a group of yellow pigments produced in our laboratories from Pb, Sn and Sb elements or compounds were selected in form of powders. These pigments were previously characterized through XRF spectroscopy, SEM-EDS analysis, micro-Raman spectroscopy and reflectance spectrophotometry in the visible range.

37

DETECTİON, İDENTİFİCATİON AND CLASSİFİCATİON OF ASBESTOS FİBERS AND ASBESTOS CONTAİNİNG MATERİALS

(ACMS) BY İNNOVATİVE OPTİCAL SENSİNG DEVİCES

Giuseppe Bonifazi1 and Silvia Serranti2

1 Department of Economics, Engineering, Society and Business

Organization,University of Tuscia, Viterbo, Italy 1 Department of Chemical Engineering Materials Environment,

Sapienza University of Rome, Italy * contacting author: giuseppe.bonifazi@uniroma1.it

ABSTRACT: The extensive use of asbestos has therefore led to the presence of fibers in existing buildings and within the construction and demolition waste. For this reason, a fast, reliable and accurate recognition of ACMs represents an important target to be reached. In this paper the use of micro X-ray fluorescence (micro-XRF) technique coupled with a statistical multivariate approach was applied and discussed with reference to ACMs characterization. Different elemental maps of the ACMs were preliminary acquired in order to evaluate distribution and composition of asbestos fibers, then samples energy spectra where collected and processed using chemometric methods to perform an automatic classification of the different typologies of asbestos fibers. Spectral data were analyzed using PLS-Toolbox™ (Eigenvector Research, Inc.) running into Matlab® (The Mathworks, Inc.) environment. Data pre-processing to enhance collected spectral features and data explorative analysis, based on Principal Component Analysis (PCA), was first carried out. An automatic classification model was then built and applied. For each investigated sample, a false color prediction map was obtained. Results showed that asbestos fibers were correctly identified and classified according to their chemical composition. Asbestos is the common name used for two families of fibrous minerals of different crystallographic and chemical characteristics: serpentine (i.e. chrysotile: Mg3(Si2O5)(OH)4) and amphiboles (i.e. crocidolite: Na2(Fe

2+3Fe

3+2)Si8O22(OH)2 and amosite:

Fe7Si8O22(OH)2. They can all exist in several different crystalline forms, but only if characterized by a fibrous structure they are classified as asbestos. The most used mineral in the industrial sector is chrysotile, as it is contained in almost 95% of all asbestos products and/or artifacts. Among the amphiboles, the most widely used mineral is crocidolite, followed by

38

amosite. Asbestos has been widely used in many applications for its technical properties (i.e. resistance to abrasion, heat and chemicals). However, despite its properties, asbestos is recognized as a hazardous material to human health and since 1980 it has been banned in many industrialized countries. The extensive use of asbestos has therefore led to the presence of fibers in existing buildings and within the construction and demolition waste. The exposition of people to asbestos is quite huge. World Health Organization (WHO) report shows as about 125 million people are exposed to asbestos at the workplace. Every year, asbestos-related-tumors produce the death of about 100,000 people, several thousand related to asbestos exposure at home. Additionally, fiber identification techniques are crucial for environmental control in contaminated areas such as the proximity of an asbestos mine. For this reason, the possibility to adopt fast, reliable and accurate analytical methods to detect, identify and classify asbestos fibers and Asbestos Containing Materials (ACMs), represents an important target to be fulfilled both at laboratory and “in situ” scale. In this paper the use of innovative optical sensing devices coupled with chemometric techniques was applied and discussed with specific reference to the future applicability of this approach in respect of the well established, and actually currently utilized, analytical approaches.

39

LASER SINTERING OF BINARY MIXTURES OF CERAMIC POWDERS

Daniele Sofia1, Diego Barletta1, Massimo Poletto1

Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132; 84084, Fisciano, SA, Italy

email: dsofia@unisa.it ABSTRACT: In selective laser sintering (SLS) laser is used to sinter particles in a layer of powders. With subsequent increments of powder layers it is possible to create three dimensional structures. This technique can be used in prototyping applications able to produce customized objects of predetermined shape. With SLS it is possible to process polymer, ceramics and metal. In SLS techniques, increasing the energy transferred by laser increases the strength of the structure obtained, but it also produces a volume of contraction of the sintered material which reduces the precision of the final object. It is possible to use two different ceramic materials with different melting temperatures, to combine the different characteristics of the starting materials. Since the energy required for sintering depends on the particle size. The use of smaller particles allows for the use of smaller energies and therefore the production of complex and more precise structures two to reduced melting. In the present study of binary mixtures made of soda lime glass beads and hydroxyapatite are studied by changing the size of the glass beads. The powder composition and the powder laying procedure have been studied and optimized in order to obtain specific properties with the mechanical properties desired for scaffold. The equipment used is a laser sintering device that uses a specially constructed 40 W CO2 laser beam. Single layer square artefacts of 10 mm side were produced and characterized measuring the layer mass, thickness, apparent density and flexural strength. This latter test was used to estimates the material tensile strength. A simple model approach is used to correlate changes observed in the strength material strength and to estimate the strength of the sintered contacts.

40

ROLE OF SPREADING SOLUTION SOLVENT IN DETERMINING THE MORPHOLOGY OF PVDF FILMS DEPOSITED BY

LANGMUIR-BLODGETT METHOD

Ajit Seth1, Isha Kalra1 and Loveleen K. Brar

1School of Physics and Materials Science, T.I.E.T., Patiala 147004, India

1Both authors have equal contribution.

ABSTRACT: The β-phase of PVDF homopolymer meets the hot spot for piezoelectricity, pyroelectricity and ferroelectricity. The Langmuir-Blodgett (LB) technique has emerged as an effective method for producing thin films of β-PVDF. Transparent films of β-PVDF can be synthesized by deposition of multiple layers of PVDF Langmuir layers from the air-water interface onto a hydrophilic substrate followed by drying and annealing above its Curie temperature. The morphology of the films deposited by LB method depends on 3 factors: compaction and elasticity of the Langmuir monolayer at the air water interface, transfer parameters and morphology of the substrate. The properties of the Langmuir monolayers are in general determined by temperature of subphase and barrier compression rate. PVDF does not have a well-defined hydrophilic head and hydrophobic chain. We believe its interactions with the solvent used for making the spreading solution will determine to a large extent how it spreads on the water-air interface. In this work we have used NMP and MEK as polar aprotic solvents to determine the role of spreading solution solvents. Langmuir films formed for both the solvents were characterized by the surface pressure – area (Π-A) isotherms at different compression rates and subphase temperatures. The Langmuir films for the two solvents show very distinct properties. For both the both the solvents the optimum conditions for best transfer were determined. The corresponding PVDF LB films were characterized with atomic force microscopy after drying and annealing. Our results show that the swelling properties of MEK, when mixed with polymers, leads to Langmuir films with lower compaction and LB films which have higher rms roughness. The strong hydrogen bonding between PVDF- NMP molecules supported the formation of a stable PVDF (NMP) Langmuir film and afforded them the transfer ability on different substrates (mica, glass and ITO-coated glass).

41

EFFECTIVE PREPARATION OF CURCUMIN NANOPARTICLES BY STIRRED MEDIA MILLS

Rahul Jaijan1, Kanika Meena1 and Chetan M. Patel1*

1Department of Chemical Engineering, Sardar Vallabhbhai National Institute of Technology Surat -395007, Gujarat, India, *Corresponding

author. E-mail: cmp@ched.svnit.ac.in ABSTRACT: Curcumin is highly potent, nontoxic, bioactive agent present in turmeric, which is utilized in household remedy to cure many ailments. The poor water solubility is one major limitation for its utilization in curing diseases. Different methods have been proposed in the literature to prepare curcumin nanoparticles with enhanced water solubility. In this work we investigated an efficient method for obtaining nanoparticles by mechanical method. The wet-milling process in stirred media mills was used for preparation of curcumin nanoparticles using tween 80 as surfactant. Nanoparticles were produced by varying the different parameters of milling such as milling time, size of grinding beads, surfactant concentration. The particle size of prepared nanoparticles was measured by Dynamic Light Scattering (DLS) technique and Transmission Electron Microscopy. The chemical composition and the effect of milling on the crystallinity of curcumin was analyzed by Fourier-Transform Infrared spectroscopy and X-Ray Diffraction. Stability of curcumin nanoparticles was analyzed over period of time using Turbiscan.

42

FACILE IMMOBILIZATION OF IRON ON CARBON NANOSPHERES USING ORGANOMETALLIC-COMPLEX FOR

SUPERCAPACITOR APPLICATIONS

Aashima Mahajan2, Raveena Choudhary1, Ashok Kumar2, Manmohan Chhibber2 and Loveleen K. Brar1

1 School of Physics and Materials Science, T.I.E.T., Patiala 147004, India

2 School of Chemistry and Bio Chemistry, T.I.E.T., Patiala 147004, India

Corresponding Author: brarloveleen@thapar.edu ABSTRACT: Sustainable future requires a shift of the energy production as well as energy storage to cleaner sources. Electrochemical energy storage solutions such as supercapacitors have emerged as attractive candidates for the energy storage in recent times. Carbon based supercapacitors with metal/metal oxide/metal hydroxide composites show enhanced energy density properties which are otherwise lacking in purely carbon based systems. Uniform and mesoporous carbon nanospheres (CNSs) find applications in multiple areas of research like supercapacitors, electrocatalysts, batteries and gas sensors etc. Smooth CNSs of average diameter 470 nm, prepared from sucrose by hydrothermal method were used in this work. The iron has been immobilized on the surface of CNSs by sonication method using an organo-metallic complex, tris-(1,10-phenanthroline)-iron (II) sulphate. The organo-metallic complex as well as the synthesized CNS-Iron powders were characterized using UV-Visible Spectroscopy, FTIR, SEM and BET surface area analyzer as applicable. Different samples of CNS having varying percentage of immobilized iron were synthesized. FTIR as well as UV-Vis results were used to delineate that the amount of iron immobilized on the samples is changing from partial to complete coverage of the CNSs. The Fe immobilized CNSs demonstrate good applicability for super capacitor applications as electrode. The capacitance measurements were done using a three-electrode setup with the working electrode consisting of: CNS-iron powders on a glassy carbon electrode. The Cdl value was best for CNS partially immobilized with Fe showing more than 20 times enhancement as compared with the bare CNS samples.

43

MIXING BEHAVIOR OF BINARY MIXTURES IN A SPOUT-FLUID BED: DESIGN OF EXPERIMENTS APPROACH

Sujan Kumar Bhashapaka2, Vedala Sree Teja3, Vidyasagar

Shilapuram4, Venu Vinod Ananthula1

1, 3, 4Department of Chemical Engineering, National Institute of

Technology, Warangal, Telangana 506004, India 2Department of Chemical Engineering, BIT Sindri, Dhanbad,

Jharkhand 828123, India

ABSTRACT: In the present study, mixing behavior of binary mixtures in a spout-fluid bed was modeled using statistical design approach viz., design of experiments (DOE). Gas velocity, particle diameter ratio, mixture composition, initial bed arrangement and sampling time have been considered as input variables and the mixing index is considered as the response of the spout-fluid bed system. A factorial design approach was considered with different levels for each system parameter as a factor affecting the mixing behavior. Various models such as linear, two factor interaction, quadratic, and cubic were tested for the model adequacy. Results show that the quadratic model is suggested. The interaction among the factors was only revealed by the DOE approach. Results show that the time and composition interactions along with their quadratic affects are dominant. The developed model was verified by using various statistical tests, and validated with the experimental data.

44

MULTI INPUT SYSTEM MODELING AND FRACTIONAL ORDER CONTROL OF CUTTING FORCES IN MACHINING

NANOCOMPOSITES

Ravi Sekhar1, T. P. Singh2, Pritesh Shah3

1Research Scholar, Symbiosis Institute of Technology, Symbiosis

International (Deemed University), Pune, India 2Department of Mechanical Engineering, Thapar Institute of Engineering

& Technology, Patiala, India 3Symbiosis Institute of Technology, Symbiosis International (Deemed

University), Pune, India ABSTRACT: Quality control is an important industry requirement. Keeping cutting forces under control is critical to quality of machining outcomes like surface roughness. Optimum cutting forces also help in reducing and preventing excessive tool wear and work damage. This is especially the case for hard to machine materials, such as nano metal matrix composites. In this work, machining system models were identified with multiple inputs (speed, feed rate, depth of cut) and single output (cutting force). These models were based on experimental data of machining aluminum (AA6063)-carbon nanotube (0.3, 0.5, 0.7 wt.%) metal matrix composites. Different model structures were explored, such as autoregressive with exogenous variables (ARX), autoregressive moving average with exogenous variables (ARMAX), output error (OE) and Box–Jenkins (BJ). The best model among these (OE 222) was selected (for control) based on indices such as minimum mean square error (MSE), best FIT, and the minimum possible number of model parameters. Thereafter, fractional PID (FOPID) controller was used to control machining force generation using the selected model (OE 222). Feed rate was selected as the manipulated variable whereas speed and depth of cut were given constant inputs as per the experimental design. Genetic Algorithm was employed to optimize fractional PID controller parameters to obtain the best possible control characteristics. The controller output signal (cutting force) attained the desired set point (130 N) with a settling time of just 49 seconds and maximum overshoot of only 10%. Low settling time of control signal at the desired force magnitude exhibited good machining productivity from such control. Low value of maximum force signal overshoot ensured tool and operator safety. The control signal (feed rate) settled at a value close

45

(error: 4.9 %) to the experimental feed setting corresponding to the resultant cutting force selected as the control set point.

46

MICRO AND NANO PARTICLE COMPOSITE MACHINING: FRACTIONAL ORDER CONTROL OF SURFACE

ROUGHNESS

Ravi Sekhar1, T. P. Singh2, Pritesh Shah3

1Research Scholar, Symbiosis Institute of Technology, Symbiosis

International (Deemed University), Pune, India 2Department of Mechanical Engineering, Thapar Institute of Engineering

& Technology, Patiala, India 3Symbiosis Institute of Technology, Symbiosis International (Deemed

University), Pune, India ABSTRACT: Particle reinforced composites are difficult to machine materials. It is important to understand the effects of different particle materials and particle sizes on composite machining outcomes. In this work, micro sized boron carbide (3, 5 and 7 % by weight) and carbon nanotube (0.3, 0.5 and 0.7 % by weight) particle reinforced aluminum (Al6063) matrix composites were machined. Experimental design involved variations of cutting speed (75, 125, 175 m/min), feed rate (0.1, 0.15, 0.2 mm/rev) and depth of cut (0.25, 0.75, 1.25 mm) one at a time, keeping the other two parameters constant at their mid levels. Nine experimental runs were planned to cover three variations each of the three input parameters. These nine runs were repeated for the three particle compositions each of boron carbide and carbon nanotube particles. Thus, the total number of runs for micro and nano particle compositions each came to 27. These 27 runs were converted into 27 time step inputs (0 - 26) for system identification (modeling) of surface roughness generation. Thereafter, a fractional order controller was designed to control surface roughness at 1 micron output. Results indicate the comparative difference between machined surface roughness trends of micro and nano particle composites. Machined surface roughness values of carbon nanotube composites are significantly high for their very low reinforcement fractions. This may be attributed to the superior strengthening mechanisms of carbon nanotube particles, like the peeling effect. Controller outputs indicate that better characteristics (overshoot, settling time) are obtained for nano particle reinforced materials as compared to the micro particle composites as per the scope of the present study.

47

INNOVATİVE OPTİCAL SENSİNG ANALYTİCAL ARCHİTECTURE FOR MİCROPLASTİCS DETECTİON, İDENTİFİCATİON AND

CLASSİFİCATİON

Giuseppe Bonifazi1 and Silvia Serranti1

1

Department of Chemical Engineering Materials Environment, Sapienza University of Rome, Italy

*

contacting author: giuseppe.bonifazi@uniroma1.it

ABSTRACT: The presence of plastics in the marine environment represents one of the most challenging environmental problems to face in respect of the negative effects, not only at biological and/or ecological level, but also in a wider economic perspective. The presence of waste plastics in marine environments is responsible to promote invasive species transport and damage to public health. Furthermore, shoreline plastic negatively affects shipping, energy production, fishing and aquaculture resources. A quantitative evaluation of the overall economic impact of plastics to marine ecosystems is not easy to account, but it was estimated downward that it is roughly around ~$13 billion US/year. Marine debris impact affects several hundred of species, ranging from zooplankton to whales. Obviously also fishes we eat are included in this list. The risks associated to marine plastic pollution are dramatically high due to the potential of this ubiquitous pollution form to accumulate organic contaminants, such as carcinogenic polychlorinated biphenyls (PCB), polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs), as well as toxic metals. Marine waste plastics individuals can be roughly divided in 5 classes: megaplastic (>100 mm), macroplastic (from 100 to 20 mm), mesoplastic (from 20 to 5 mm), microplastic (< 5 mm). Microplastics can be further divided in: “primary” and “secondary” according to the source generating them. In the case of the primary microplastics, they derive from specific manufactured products (i.e. resin beads, cosmetic products, clothing, etc.). Secondary microplastics derive from larger polymeric products milling both from human intervention and/or natural alteration. Microplastics enter in the marine environment via terrestrial and marine-based activities. The mobility of the microplastics in the marine environment (e.g. sinking or floating behaviour) is strongly influenced by intrinsic parameters as the size or the polymeric composition. Plastic density is one of the key factors affecting microplastic behavior in the

48

ocean. Density, in fact, depends not only by polymers chain, but also by the additives usually utilized to enhance specific characteristics of the polymer based manufactured product. Polymers structure and additives are also responsible of microplastics degree of degradation in respect of specific environmental conditions (e.g. sea temperature) and exposure time. From these considerations, it is clear the importance to perform a fast and reliable characterization of microplastics, ideally “in situ”, in order to primarily understand and monitor their behavior and to set up efficient mitigation actions. A major obstacle to reach this goal is related to the analytical effort needed to characterize polymeric composition, morphological and morphometric attributes or level and characteristics of degradation. Actually, polymers identification is time consuming and expensive, especially with the need to analyze high number of samples in order to acquire sufficient information to set up robust conclusions. The hyperspectral imaging (HSI) based approach can represent an important analytical tool that, in respect of commonly applied analytical techniques, as FTIR and Raman spectroscopy, allowing to analyze a large number of samples per unit time. Combining morphological and morphometrical analyses with polymer identification, HSI allows to give deep information about the characterization of marine microplastics. In this paper Short Wave Infrared (SWIR) HSI was used to identify the polymers constituting microplastic debris and this information was analyzed together with the particle morphological attributes in order to achieve a full characterization.

49

POWDER SIMULATION

50

NUMERICAL SIMULATION OF ONE DIMENSIONAL CONSOLIDATION TEST OF MONTMORILLONITE/KAOLINITE

MIXTURES USING DISCRETE ELEMENT METHOD

Moein Khabazian1, Ali Asghar Mirghasemi1, Hamed Bayesteh2

1School of Civil Engineering, College of Engineering, University of Tehran,

Iran 2 Department of Civil Engineering, University of Qom, Qom, Iran

ABSTRACT: In this study, the investigation of volumetric changes in soil containing montmorillonite and kaolinite and mixtures of the two has been carried out using the discrete element method (DEM). In order to achieve this goal, seven clay samples containing montmorillonite (in lengths of 100, 200 and 300 nm) and kaolinite (in lengths of 1, 2 and 3 μm) were prepared using the DEM by modeling all physicochemical forces between particles during consolidation testing. Clay particles are modelled under flexible and non-flexible conditions and the results are compared with those from laboratory testing. The results show that the numerical solution of flexible particles is more in agreement with experiments compared to the rigid particles at high consolidation pressures (pressures more than 1000 kPa). In order to verify the proposed method for calculating DDL force between two particles of two minerals, the consolidation curves for samples containing 35% (M35) and 65% montmorillonite (M65) are compared with the experimental results. It can be observed that, for M35 and M65, the consolidation curves for loading and unloading are in agreement with the experimental results. In addition to the M35 and M65 samples, the consolidation tests for the 50% calcium-montmorillonite and kaolinite content (M50) and the 100% calcium-montmorillonite (M100) and kaolinite (M0) were done. The consolidation coefficients along the loading and unloading paths were found to be dependent upon the montmorillonite content of a given mixture and it can be seen that the samples with higher montmorillonite contents had higher porosities at the same consolidation pressure. This is due to the contribution of physicochemical forces (especially DDL forces) on clay behavior. Finally, the relationship between the loading and unloading consolidation coefficients and montmorillonite content was investigated.

51

PARTICLE BREAKAGE MODELLING OF GRANULAR MATERIALS

IN DIRECT SHEAR TEST USING DEM-XFEM

S.M. Seyyedan1, A.A. Mirghasemi1 and S. Mohammadi1

1School of Civil Engineering, College of Engineering, University of Tehran,

Iran ABSTRACT: Particle breakage is an important issue that affects the mechanical behaviour of granular materials in many geotechnical structures, such as rockfill dams. Since large-scale experimental tests on rockfill materials such as triaxial and direct shear tests are difficult and costly, it is required to use numerical modelling to assess the effect of particle breakage on their macro- and micro-mechanical behaviour. The Finite Element Method (FEM) is one of the most common tools to predict the behaviour of various materials. Despite its popularity, FEM suffers from certain drawbacks when the solution contains discontinuities in the displacement field such as jumps, kinks, or includes stress singularities. Singular elements, adaptive finite element procedures, and combined finite/discrete element methodologies have substantially contributed to the development and accuracy of fracture analysis of structures, but the continuum basis of FEM remained a source of relative disadvantage for discontinuous fracture mechanics. In order to overcome such difficulties, the eXtended Finite Element Method (XFEM) has been specifically designed for treating such discontinuities. Also, the Discrete Element Method (DEM) is a particle-scale numerical method for modelling the behaviour of granular materials and many geomaterials such as soil and rocks. In this article, a novel approach for numerical simulation of particle breakage in direct shear test has been developed using combined DEM and XFEM. The fracture within individual particles is modelled with XFEM, while the particle motion is simulated through DEM approach. Using this new approach in the modelling of particle breakage in granular materials offers a computational advantage in comparison to DEM-FEM coupling. Finally, the effect of particle breakage on macro- and micro-mechanical behaviour of granular materials is presented.

52

NON-LINEAR BREAKAGE AND INSIGHTS FROM DEM–PBM SIMULATIONS

Ecevit Bilgili1

1Department of Chemical and Materials Engineering, New Jersey Institute

of Technology, Newark, NJ 07102, USA ABSTRACT: Population balance models (PBMs) have been used to model the evolution of particle size distribution (PSD) during milling processes. The fundamental tenet of traditional PBM for milling is the linearity of breakage rate, i.e., first-order breakage kinetics. In the first part of this keynote, I present experimental studies that provide evidence for the emergence of non-linear breakage: deviations from first-order breakage kinetics, significant impact of initial PSD on the breakage kinetics, anomalies in binary breakage tests, etc. The non-linear breakage appears to be prevalent in dense milling systems such as in dry ball mills, where enduring mechanical multi-particle interactions occur. In the second part of my talk, highlights from recent theoretical developments that address this complex phenomenon of non-linear particle breakage will be given. Modeling of dry ball milling systems and particle bed breakage experiments suggests that the non-linear Bilgili–Scarlett model can serve as a unified framework by which non-linear particle breakage in a multitude of comminution systems can be described. Finally, the presentation will highlight recent efforts in exploring the origin of non-linear breakage via discrete element method (DEM)–PBM and using such multi-scale models to predict the evolution of PSD during dry ball milling.

53

CALIBRATION OF DEM FOR COHESIVE PARTICLES IN THE SLS POWDER SPREADING PROCESS

Marco Lupo1, Mehrdad Pasha2, Daniele Sofia1, Diego Barletta1, Mojtaba Ghadiri2 and Massimo Poletto1

1Department of Industrial Engineering, University of Salerno, via Giovanni

Paolo II, 132, 84084 Fisciano (SA), Italy 2Faculty of Engineering, University of Leeds, Leeds LS2 9JT, UK

ABSTRACT: Additive manufacturing (AM) is getting more and more interest due to the possibility to create objects in very complex shapes and at different sizes (nanoscale to large parts). Among the AM processes there is the Selective Laser Sintering (SLS) which allows to create artifacts by selectively sinter particles in a single powder layer by means of a laser. One crucial step of SLS is the spreading of the powder to form a thin layer. The way in which the powder is distributed depends on several factors such as the spreading tool, the environmental conditions as well as the powder itself. Aim of this research project is to simulate the distribution of powder at different process conditions by means of the Discrete Element Method (DEM) to understand the mechanisms and the powder properties which affect the quality of the layer. However, to properly simulate the spreading, it is necessary to insert in the DEM software the right values of same parameters which are the input variables necessary to evaluate the forces between the particles. In this paper a calibration procedure, based on the simulation of the unconfined compression test, is presented to infer the interfacial adhesive surface energy.

54

EXPERIMENTAL INVESTIGATION OF SEGREGATION OF NON-SPHERICAL PARTICLES IN A FLUIDIZED BED SOLIDS-

MIXER

Sanjay Kumar Verma1, Jeetram Yogi2 and Anshu Anand3

1,2,3 Department of Chemical Engineering, Indian Institute of Technology

Roorkee 247667, India

ABSTRACT: A binary mixture of spherical particles have a tendency to segregate based on the differences in size in different flow situations. Most of the granular particles found in the industries are generally non-spherical. In the present work, we have established an experiment to study the evolution of the segregation and its dependence on both the shape and size of the particles. Different shapes like spherical, ellipsoids (prolate and oblate), cubical, elongated needle have been used. Studies have been carried out in a fluidised bed. We have carried out the study by fixing on of the particle of a binary mixture to be sphere and varying the shape of the other particle while operating in different flow regime. Our results indicate that the segregation index at steady state value depends only on the shape of the larger particle but is dependent of the shape of smaller particle. These results have important industrial design implications and provide important heuristics to decrease segregation by choosing the shape of the particles.

55

IMPLEMENTATION OF COHESIVE DEM TO STUDY AGGLOMERATION OF NANOPARTICLES

Alok Tiwari1**, Vikul Tomar1* and Manaswita Bose1

1**, 1*, 1 Department of Energy Science and Engineering, IIT Bombay,

Mumbai 400076, India **

Corresponding Author E-mail: alok.tiwari@iitb.ac.in

ABSTRACT: Agglomeration of nanoparticles presents a challenging and intuitive research problem where particles are attracted by weak van der Waals forces forming agglomerates. In recent years, various computer simulation methods are used to analyse different properties of agglomerates that are difficult to study using the available experimental techniques. This paper investigates the behaviour of dry TiO2 nanoparticles, confined in a two-dimensional periodic box. Molecular dynamics simulation is performed where contact force is modelled using the soft sphere approach. Particle integrated van der Waals force is considered for the cohesion between particles. Fractal dimension obtained using simulation are compared with the experimental results of the similar TiO2 nanoparticles. Porosity of the stable agglomerate is determined using three different methods. Other microscopic properties like mean coordination number have been calculated to check the dynamic behaviour of agglomeration. Radial distribution function and probability distribution are plotted to confirm the crystallization in the packing of particles. Future work will examine the dynamic behaviour of agglomerates under different medium with the effect of external energy on the properties of agglomerates formed.

56

EFFECT OF THE CONTACT FORCE MODEL ON THE BULK FLOW BEHAVIOR OF GRANULAR MATERIALS IN DEM

SIMULATIONS

Satyabrata Patro1 and Anurag Tripathi2

1Department of Chemical Engineering, Indian Institute of Technology,

Kanpur 208016, India ABSTRACT: DEM (Discrete element method) simulations are the most popular tool used to simulate the behaviour of granular materials. Out of various possible particle-particle contact force models, the linear spring and dashpot (LSD) model and the Hertz model are commonly used by researchers. The interactions at the particle level have been investigated by many researchers using different contact force models. However, comparison of these different models on the flow behaviour of the material has received relatively little attention. Qualitative similarity between the velocity profile and solids fraction for chute flow over an inclined surface was observed by using the LSD and Hertz model, significant quantitative differences were noticeable. To investigate the origin of these differences, we perform chute flow simulations using these two different contact force models. In agreement with the authors, we observe that the granular material modelled using the Hertz contact model flows significantly faster with a lower value of the solids fraction and higher flowing layer thickness. Detailed analysis of the particle level interaction force suggested that the difference reported by the authors might be due to the fact that the restitution coefficient of the particles in the two models differs significantly from each other. The contact model parameters in the Hertz model were adjusted to obtain the value of the restitution coefficient identical to that of the LSD model and the revised simulations using the two models had identical values of the two most important physical properties: normal restitution coefficient and friction coefficient. However, the results from the revised Hertz model parameters did not agree with those from the LSD model. The discrepancy in the results from the two contact force models despite identical physical properties is discussed in this work. These observations raise fundamental questions about the assumed equivalence of the two contact models at a macroscopic level.

57

MEASUREMENT OF THE ROLLING FRICTION OF IRON ORE PELLETS FOR USAGE IN DEM SIMULATION

Arpit Agarwal1, Akash Jangale1, Krishna Gupta1 & Anurag

Tripathi1

1Department of Chemical Engineering, Indian Institute of Technology

Kanpur, 208016, India ABSTRACT: DEM simulation of bulk solids requires careful calibration of the involved simulation parameters. DEM studies comparing simulations with experiments suggest that value of the rolling friction of the particles used in the simulations has a strong influence on the bulk behavior of the material. While the parameters such as restitution coefficient and sliding friction coefficient can be estimated by means of drop-and-bounce or sliding-on-a-plane type experiments, estimation of the rolling friction by means of simple experiments remains challenging. In this work, we present a novel way to estimate the rolling friction of spherical steel balls and slightly aspherical pellet particle rolling over an inclined plane. By using high speed videography, we record the motion of steel balls and pellet particles rolling over a flat inclined surface. The recorded video is converted to individual image frames and the obtained images are corrected for the perspective error to nullify the distortion of the image portions due to different distances form the camera lens. The position of the rolling particle in each frame is identified using image processing toolbox of Matlab. The distance travelled by the particle along the incline shows a quadratic variation with time, indicating a constant acceleration down the incline. In order to relate this acceleration with the rolling friction, the motion of a sphere rolling over an inclined plane is theoretically described using the equation of motion by accounting for the presence of the rolling friction. Using this theoretical relation, we find that while the rolling friction of steel balls is small (~0.01),that of the iron-ore pellet is ~0.07 and hence should not be neglected in DEM simulations. DEM simulations using this measured value of the rolling friction were performed using EDEM® academic software and are found to be in very good agreement with experimental results for iron ore pellet flow rate through a cylindrical hopper.

58

MULTI-SCALE SIMULATION OF THE PELLET ROUNDING IN A SPHERONIZATION PROCESS WITH DIFFERENT FRICTION

PLATES

Dominik Weis1, Maria Evers2, Markus Thommes2, and Sergiy Antonyuk1

1Institute of Particle Process Engineering, Technische Universität

Kaiserslautern, 67663 Kaiserslautern, Germany 2Chair of Solids Process Engineering, Technische Universität Dortmund,

44227 Dortmund, Germany ABSTRACT: Spherical pellets with a narrow size distribution and a homogeneous surface are highly interesting for pharmaceutical applications. To produce such pharmaceutical pellets, a combined extrusion and spheronization process is widely used. A spheronizer consists of a stationary cylindrical wall and a rotating disk with a structured surface called friction plate. The pellet rounding of the cylindrical extrudates in the spheronizer is based on different formation mechanisms which are dependent on the particle dynamics. Since those mechanisms run in parallel and additionally affect each other, there is no sufficient understanding of the process so far. Therefore, simulations of the process can help to get more detailed information on the pellet rounding in a spheronizer. Simulating the process is challenging because effects on different time scales need to be considered. On the one hand, the interactions of the wet, plastic and adhesive pellets, which occur on the micro scale, need to be resolved. For this reason, a new contact model for the wet pellets was developed. On the other hand, the overall pellet rounding happens on the macro scale. Therefore, the process was simulated on multiple time scales by a coupling of the Discrete Element Method (DEM) and a Population Balance Model (PBM) in this study. This simulation framework enables both, a resolved description of the pellet interactions as well as a prediction of the changing pellet shape. A researcher found that the pattern of the friction plate can affect the formation of the pellets. For this reason the effect of the friction plate geometry on the pellet rounding is analyzed in this study. Four different friction plate geometries were used in the simulations. Beside a planar plate a), a cross hatched b), a radial c), and a striated edge pattern d) were used.

59

CFD SIMULATION OF PRESSURE DROP IN SLURRY PIPELINE FOR FLOW OF SAND WATER SUSPENSION

Varinder Singh1, Satish Kumar2, Dwarikanath Ratha3

1Mechanical Engineering Department, Thapar Institute of Engineering

and Technology, Patiala, 147004, India 2Mechanical Engineering Department, National Institution of

Technology, Jamshedpur, Jharkhand 831014, India 3Civil Engineering Department, Thapar Institute of Engineering and

Technology, Patiala, 147004, India

ABSTRACT: The present study is focused on to investigate the pressure drop due to sand slurry flow through straight pipe using 3D CFD simulation. The Numerical simulations of straight pipes have been carried out using Eulerian-multiphase model of CFD code FLUENT. The Standard k-ω model shows a best suitable comparison with experimental results for further investigation. The domain of geometry has been discretize by 3D grid of hexagonal shape. In the present study, the water have been taken as a primary phase and sand particles is taken as a secondary phase. The diameter of pipe was taken as 100mm. The slurry concentration have been varied to 10-40% (by weight) for flow velocity of 1-4 m/s with average particle size of 150µm. The volume fraction, flow velocity and contours of turbulence intensity are obtained at the inlet, outlet and center location of pipe geometry at different concentration and velocity. The pipe material was taken as mild steel with the density of 7850 kg/m

3. The density of sand

and water was taken as 2650 kg/m3 and 1000 kg/m

3. From the results, it is

observed that flow velocity dragged the solid particles from the bottom of the pipe. Also, from the velocity contours, it is revealed that an increase in flow velocity results in flow separation along with the pipe.The pressure across the straight pipe increases as the slurry concentration increasing.

60

DEM SIMULATION OF PACKING SPHERICAL PARTICLES IN TO SLENDER PRISMATIC CONTAINERS

Sujith Reddy Jaggannagari1, Raghuram Karthik Desu1, Ratna

Kumar Annabattula1

1Department of Mechanical Engineering, Indian Institute of Technology

Madras, Chennai 600036, India ABSTRACT: The thermal/mechanical behaviour of a granular assembly depends on various factors like packing structure, packing density, friction between particles, particle size distribution and container geometry. The filling strategy of the particles into the containers plays a critical role in the resulting packing structure. A thorough investigation of various packing strategies and the resulting packing structure provides more insights into the underlying mechanism. With the help of Discrete Element Method (DEM), it is possible to gain access to the particle level interactions and establish a connection between the particle-scale interactions and the macroscopic behaviour of the granular assembly. An open source DEM software LIGGGHTS is used to simulate the filling of spherical particles (diameter = 2.4 mm) into a slender prismatic container (20 mm X 80 mm X 80 mm) under gravity assisted by container vibration. The transient evolution of packing structure under the action of an external sinusoidal excitation of the container has been investigated. Monodisperse and polydisperse granular assemblies are studied to understand the particle size effect on the packing structure of the assembly. The simulation results are in good agreement with X-ray computed 3D tomography results. The results of simulations show that vibration drives the particles to get settled in a regular arrangement in the assembly. As the vibration time progresses, particles rearrange to stable configuration, enhancing the packing fraction of the assembly to a steady state value.

61

POWDER-BASED SIMULATIONS FOR SELECTIVE LASER SINTERING AND SELECTIVE LASER MELTING

Alvaro A. ESTUPINAN DONOSO1, Bernhard PETERS1 and

Rice KABORE

1 “Faculté des Sciences, de la Technologie et de la Communication”,

University of Luxembourg, Esch sur Alzette, Luxembourg ABSTRACT: Multi-physics characteristics that take place on different length-scales are employed to unveil the underlying physics of the sophisticated additive manufacturing techniques to cover both the design stage and qualification/certification. Euler-Lagrange techniques as a coupling between a continuous and discrete phase are appropriate and effective numerical approaches when employed to additive manufacturing processes. The above-mentioned approach treats powder and its physics such as transport and melting by an extended discrete element method (XDEM) while finite element (FE) and finite volume (FV) methods deal with continuous phenomena such as temperature distribution, melting or solidification. This contribution presents the XDEM methodology as an alternative to predict the laser melting and the laser sintering of powder beds. For the latter, the prediction of the liquid phase transfer to a continuous domain is also accounted. The powder bed preparations, particles deposition and leveling by cylindrical roller, are simulated with the same methodology. After leveling, information on the bed density is provided prior to laser scanning. The presented methodology captures the laser interaction with the bed, including possible phase change and heat and mass transfer. This contribution presents results for the laser particle interaction, particles coalescence, as well as the melt pool formation in the continuous. In addition, temperature and species histories inside particles and in melt pool can also be evaluated. The current state of the presented comprehensive output can be employed to optimize laser power input, scan strategies, bed heights to diminish the existing AM challenges, e.g. partial melting, spattering, melt voids and denudation.

62

NUMERICAL ANALYSIS OF THE DRAG COEFFICIENT OF SPHERE FALLING IN NEWTONIAN FLUID WHILE SURROUNDED BY OTHER SPHERICAL PARTICLES

Labhini Arundasji Pagarware1, and Basudeb Munshi2

1, 2

Department of Chemical Engineering, National Institute of Technology, Rourkela, Odisha, Pin: 769008, India

ABSTRACT: Over the years, considerable research effort has been made in studying the drag phenomena of single particles in incompressible Newtonian fluids. The behavior of a single sphere has gained the maximum attention. But in industrial processes, there are number of particles fall together. The fluid dynamics of other moving particles certainly affect the drag coefficient of a particular falling particle. The accuracy of the designed solid-fluid handling systems like fluidized bed, sedimentation process, etc. is highly governed by drag coefficient experienced by each and individual particles. Until now, no attempt has been made for finding the hydrodynamic behavior of a free falling particle in presence of neighboring particles as additional resistances along with the wall effect. This paper presents a simulation study to analyze the drag coefficient experienced by a falling sphere in Newtonian fluid surrounded by number of other spheres placed on thin ring. Further, this work also analyzes the wall effect on the estimated drag coefficient. Standard k-ω model available in ANSYS Fluent software was used for solving the CFD model equations. Initially, the CFD models were validated comparing the experimental and computed drag coefficient of the falling sphere in a pipe in absence of additional resistances. The number of spheres around the falling sphere were varied. The analysis showed that the drag coefficient decreases with decreasing the number. The variation of the size of the diameter of the neighboring spheres also depicted a depleting trend of the drag coefficient. The drag coefficient also decreased with rising the Reynolds number. Moreover, the drag coefficient was depleted with rising the blockage ratio (ds/Dp).

63

DESIGN AND ANALYSIS OF A SELF-DISPERSING TWISTED PIPE FOR FAST SETTLING SUSPENSIONS USING

COMPUTATIONAL FLUID DYNAMICS APPROACH

Harmanpreet Singh1, Satish Kumar2 and Saroj Kumar Mohapatra1

1Mechanical Engineering Department, Thapar Institute of Engineering

and Technology, Patiala, India-147004 2Department of Mechanical Engineering, National Institute of

Technology, Jamshedpur, Jharkhand, India-831014

ABSTRACT: This paper presents the results of an investigation on performance of twisted pipes in terms of the pressure loss, skin friction and mixing index for the flow of coal water suspension. The hydraulic transportation of hydrophilic or less hydrophobic particulates are often associated to settling phenomenon, due to which a stable bed of particulates is formed in the downstream region of the pipe. To mitigate the problem of particulate settling, introduction of twisted pipe sections is proposed in the present study. The experiments on the flow characteristics of the coal water slurry inside a horizontal untwisted pipe were carried out on a pilot test loop. This data was used to calibrate a CFD model based on SST k-w equations. 20 different designs of the twisted pipe sections were modelled using a commercial CFD tool, ANSYS™ Fluent. The key parameters of geometric variation in the sections are the section length (200 to 800 mm) and the number of lobes (2 to 6). As the settling usually occurs at low Reynolds number, so the flow velocity of 0.5 m/s is selected for all the cases. The maximum pressure drop was observed in the case of 2 lobe twisted pipe and showed a decrease with increase in the number of lobes. The pressure drop is found to be lesser in the short sections and shows an increasing trend with increase in the section length. The mixing index is found to be maximum for the 2 lobes pipe section, due to induction of strong turbulence inside the section and the adjacent downstream region. With the increase in the number of lobes, the degree of turbulence is observed to decrease and hence the mixing index.

64

THE FINER THINGS IN LIFE – CHALLENGES AND ADVANCES IN POWDER SIMULATION USING THE DISCRETE ELEMENT

METHOD

David R. Curry, Marina Sousani, and Stefan Pantaleev1

1EDEM, 1 Rutland Court, Edinburgh, EH3 8FL, UK

ABSTRACT: Powders are found in a wide range of industries including pharmaceutical, additive manufacturing, chemicals and other process manufacturing sectors. Here, powder materials are integral to a variety of different applications from storage, transportation and delivery to processing stages such as mixing, compaction, or agglomeration. Due to the fine sizes and wide size distribution of powder materials, their flow and behavioural characteristics are prone to even the smallest of variations in properties and operating conditions, such as moisture content and duration of storage. For Engineers designing equipment and processes that operate with powders, it is important they understand the nature of these complexities and how these will impact the design phase. The Discrete Element Method (DEM) has been employed successfully in numerous cases and is now considered a valuable predictive tool for simulating processes in powder handling industries. Furthermore, it offers virtual prediction of powder behaviour and process performance optimisation ahead of production. The success of any simulation is in its ability to replicate the material response of the real-world application with sufficient accuracy. For DEM, two key challenges associated with powder simulation are the creation of virtual materials that reflect realistic elasto-plastic behaviours (with more or less cohesion), and the computational demands of dealing with the volume of powder material present in industry-scale processes. This presentation will address these challenges by discussing the use of DEM for calibrating the input parameters to the virtual material models, and methods to reduce the computational cost without affecting the physics. These steps are necessary in order to support the industrial simulation-based-design in powder focused industries. Examples will be given that show how an effective calibration procedure can achieve close matches with real powder behaviours and demonstrate how DEM can be used in industry-scale process simulation.

65

NUMERICAL STUDY ON MIXING MECHANISM OF A RIBBON MIXER USING THE DEM

Yoshiharu Tsugeno1 and Mikio Sakai2

1 Systems Innovation, Faculty of Engineering, The University of Tokyo, 7-

3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan 2 Resilience Engineering Research Center, School of Engineering, The

University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

ABSTRACT: A ribbon mixer is often employed for powder mixing in food, pharmaceutical and chemical engineering. In this paper, numerical investigation of solid mixing is described in al ribbon mixer. In the past studies, mixing state has been examined experimentally and numerically. The discrete element method (DEM) has been employed in the computations. The DEM simulation provides valuable information because the particle mixing state can be evaluated accurately without disturbing the particle spatial location. Recently the signed distance functions (SDF) has been developed for the wall boundary model in the DEM. The SDF makes it possible to create the complex wall boundary by easy operation. Adequacy of the DEM/SDF approach has been proved through the validation tests. In the current study, the DEM/SDF method is applied to the optimization of the powder mixing in a ribbon mixer. The degree of mixing is evaluated using Lacey’s mixing index . Sensitive analyses are performed, where the parameters are rotational speed of the ribbon, the ribbon geometry and total amount of the powder. Consequently, the effective parameters are newly found through the numerical examples.

66

DEM-CFD SIMULATION FOR POWDER FILLING IN A MULTI CAVITY DIE

Rinako Yokoyama1 and Mikio Sakai2

1Systems Innovation, Faculty of Engineering, The University of Tokyo

7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan 2Residence Engineering Research Center, School of Engineering, The

University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

ABSTRACT: Powder die filling is widely employed in pharmaceutical, food and powder metallurgy. In the die-filling, it is known that the airflow might influence the resulting powder filling ratio in the die. Although the die-filling has been studied experimentally, clarification of the phenomena has been limited. This is because the bulk information including solid and gas phases cannot be obtained precisely. Recently the authors’ group has proposed an innovative Eulerian-Lagrangian method for the simulation of a gas-solid flow with a moving wall boundary. In this approach, a wall boundary model combining the signed distance function (SDF) with the immersed boundary method (IBM) has been introduced into the coupled model of the discrete element method (DEM) and the computational fluid dynamics (CFD). This methodology is referred to as the advanced DEM-CFD method. In the present study, the advanced DEM-CFD method is applied to the powder filling in a multi cavity die. In order to examine homogeneous powder filling in the multi cavity die, numerical calculations are performed. In the calculations, computational particles are moved into four dies from the shoe. The amount of the computational particles is shown to be different in all the dies because the solid particles are influenced by the complex airflow in the shoe-dies system.

67

NEXT GENERATION DEM TECHNOLOGY: CROSSING NEW FRONTIERS WITH ROCKY DEM

Saurabh Sarkar1

1Applications Engineer, Rocky DEM, CADFEM Engineering Services India

Pvt Ltd., Hyderabad

ABSTRACT: Bulk solids industries in the 21st

century are increasingly resorting to computationally driven optimization, troubleshooting and prototyping for cost effective product development. As virtual testing becomes increasingly central to product development, the onus on software providers to deliver a high-fidelity, fast and user-friendly product is greater than ever. Rocky DEM provides such a simulation package. The current talk would show several examples of how Rocky DEM has been successfully used to model real life problems across a wide range of industrial sectors like mining, food, pharmaceutical and agricultural. Examples of how industry requirements and feedback have shaped innovation within Rocky DEM would be shared.

68

ON DEVELOPING PARTICLE-FLUID COUPLED HEAT TRANSFER MODEL AT NANOSCALE

Lal Kundan1, S. S. Mallick2

1, 2

Mechanical Engineering Department, Thapar Institute of Engineering & Technology, Patiala, Punjab-147004

1kundanlalrana@thapar.edu,

2ssmallick@thapar.edu

ABSTRACT: The work highlights the nanoscale particles-fluid interaction and the heat transfer phenomenon. The effect of thermal heat conduction and induced micro-convection on the thermal conductivity of an oxide-based nanofluid (Al2O3 nanoparticles, average size 25-30 nm, in water) has been investigated. The temperature and time-dependent Brownian motion induced convection plays a crucial role in heat transport of nanofluids. The mathematical modelling based on the morphological parameters of nanoclusters reveals that the Brownian motion induced Reynolds number i.e. Brownian Reynolds number increases with the rise in temperature and decreases with elapsed time and nanocluster growth. Although, variation in the Reynolds number remains within the Stoke’s region (ReB ≤ 1). At optimized pH value, the effect of temperature on Brownian Reynolds number is found to be more significant (i.e. above 35 °C). The Brownian motion is found to be more prominent with small size nanoclusters and for elapsed time, t ≤ 24 h. The theoretical and experimental investigation has been carried out to observe the effect of time-temperature dependent volume concentration of nanoscale particles on the overall thermal conductivity of nanofluid. The experimental and theoretical results of thermal conductivity are found to be agreeing within accuracy level varying from ± 5 to ±12%.

69

ON SIGNED DISTANCE FUNCTION BASED WALL BOUNDARY

MODEL IN THE DEM SIMULATION

Mikio Sakai1

1 Resilience Engineering Research Center, School of Engineering,

The University of Tokyo

7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

ABSTRACT: The wall boundary model has not been established in the DEM simulation. Although the grid is often used as the wall boundary model in the existing DEM, there are several problems. The main problems are related to the contact detection in the DEM and the aspect ratio in the DEM-CFD method. Recently, the author’s group has developed a new wall boundary model based on scalar fields which is referred to as the signed distance function (SDF). The SDF is composed of the sign and the distance between the computational particle and the wall. The algorithm of the contact detection is simple in the SDF. Adequacy of the SDF is shown through verification and validation tests, e.g., a ribbon mixer a twin screw kneader and a three roll mill. Very recently, new wall boundary model for a fluid flow has been developed by combining the SDF with the immersed boundary method (IBM). In the SDF/IBM, the arbitrary shape wall boundary can be created by only counting number of the SDF points in a CFD grid. Hence, the arbitrary shape wall boundary can be created even if the staggered grid is employed. Adequacy of the combined SDF/IBM model is shown in a powder die-filling system and a spouted bed. Thus, both of the SDF wall boundary and the SDF/IBM wall boundary models is regarded to be innovative and might become standard wall boundary models in the DEM and DEM-CFD simulations.