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This project is a solution to an actual problem that has been given to me by the Oil spill response company, where they face problems in inspecting the seabed after an oil spill accident occurs. Usually, some of the oil that gets emulsified with sea water it sinks to the sea bed and contaminates it. The company usually sends divers to inspect, but this process is very slow. Therefore, the company requested a submersible surveillance vehicle that can be towed by a boat.
Citation preview
Final Project Towed submarine camera
Authors : Ahmed Al Bashooti 201000508 Abdulaziz Al Bufalah 20900035 Supervised by : Polytechnic: Dr.Khaled Eissa Oil Spill: Mr. Richard Sims
2013
Bishouty PC Bahrain Polytechnic
9/23/2013
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Table of Contents Table of Figures ............................................................................................................................................. 3
Abstract ......................................................................................................................................................... 6
Summary ....................................................................................................................................................... 7
Research ........................................................................................................................................................ 8
Initial sketches .......................................................................................................................................... 8
Elimination ................................................................................................................................................ 9
The chosen one ......................................................................................................................................... 9
Bio-mimicry ............................................................................................................................................... 9
Shark's body ............................................................................................................................................ 10
Windsocks ............................................................................................................................................... 11
Aerodynamics ..................................................................................................................................... 11
Material selection ................................................................................................................................... 12
Aluminum ............................................................................................................................................ 12
Carbon Steel ........................................................................................................................................ 13
Fiber glass ............................................................................................................................................ 14
Selection process .................................................................................................................................... 15
Product Design Specification Budget ....................................................................................................... 17
Equipment in the workshop .................................................................................................................... 17
Time ........................................................................................................................................................ 18
Safety ...................................................................................................................................................... 18
Knowledge and industrial skill: ............................................................................................................... 18
Environment ........................................................................................................................................... 19
Design and Manufacturing ...................................................................................................................... 20
Communication ....................................................................................................................................... 20
Milestones ............................................................................................................................................... 21
Function ...................................................................................................................................................... 22
Weight ..................................................................................................................................................... 22
Basic structure ........................................................................................................................................ 23
Installations ............................................................................................................................................. 24
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Planned Preventive Maintenance ........................................................................................................... 25
Fiberglass ................................................................................................................................................ 26
Testing ..................................................................................................................................................... 27
Construction process .............................................................................................................................. 28
Fiberglass ............................................................................................................................................ 30
Resin and Hardener............................................................................................................................. 30
Solid works .................................................................................................................................................. 31
Preparing the model for Ansys simulation ............................................................................................. 38
SolidWorks FloXpress Report .................................................................................................................. 39
Drag force................................................................................................................................................ 40
Ansys Workbench ................................................................................................................................... 41
Inserting the geometry ....................................................................................................................... 42
Geometry ............................................................................................................................................ 42
Mesh ................................................................................................................................................... 43
Setup and solutions ............................................................................................................................. 45
Results ................................................................................................................................................. 47
Discussion.................................................................................................................................................... 51
Conclusion and recommendations ............................................................................................................. 52
Appendix ..................................................................................................................................................... 53
Bibliography ................................................................................................................................................ 59
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Table of Figures
Figure 1: The first sketch ( similar to an exixting design) .............................................................................. 8
Figure 2: The second sketch idea take from (wind sovk & shark) ................................................................ 8
Figure 3 : The third sketch ( fish lure shape) ................................................................................................. 8
Figure 4 : Shark body................................................................................................................................... 10
Figure 5 : Wind sock .................................................................................................................................... 11
Figure 6: Aluminum physical properties ..................................................................................................... 12
Figure 7: The Arabian Gulf map. ................................................................................................................. 19
Figure 8: This figure illustrates the product cycle bubble map. (Product cycle ). ....................................... 20
Figure 9: The submarine body sketched by SolidWorks ............................................................................. 22
Figure 10: The body of the vehicle .............................................................................................................. 23
Figure 11: The top dome is where electronics and flash light will be installed and protected from water.
.................................................................................................................................................................... 23
Figure 12 : The rudder is a very important part, where is provides the vehicle with lateral movement ... 23
Figure 13: The bottom dome is where the camera will be installed; the material of this part must be
clear plastic. ................................................................................................................................................ 23
Figure 14: The flaps are also very important parts, where they control the vertical movement of the
vehicle. ........................................................................................................................................................ 23
Figure 15: Fiber glass application ................................................................................................................ 26
Figure 16: This figure demostrates the initiation of the sketch on the front plane ................................... 31
Figure 17: 3D sketch of the submarine outlines ......................................................................................... 31
Figure 18: Lofted body of the vehicle ......................................................................................................... 31
Figure 19: Wing sketch ................................................................................................................................ 32
Figure 20: Flap after extruding feature and chamfering the front edges. .................................................. 32
Figure 21: The top fine sketch..................................................................................................................... 32
Figure 22: The submarine body after extruding the top fine and the wings, where the flap was mirrored
to the opposite side. ................................................................................................................................... 32
Figure 23: Rudder's pivot sketch ................................................................................................................. 33
Figure 24: Pivot body mirrored ................................................................................................................... 33
Figure 25: Mirroring pivot features ............................................................................................................ 33
Figure 26: Top dome sketch, before extruding ........................................................................................... 33
Figure 27: Top dome after extruding .......................................................................................................... 33
Figure 28: Bottom dome, where the same procedure of the top dome was repeated for the bottom. ... 33
Figure 29: the submarin body after hollowing the inner part .................................................................... 34
Figure 30: The sketch of the cowling. ......................................................................................................... 34
Figure 31: The cowling after revolving the sketch ...................................................................................... 34
Figure 32: The wing after cutting the flap part. .......................................................................................... 35
Figure 33: The extruded rear wing .............................................................................................................. 35
Figure 34: The rear wing after cutting feature ........................................................................................... 35
Figure 35: The sketch of the bottom dome cover ...................................................................................... 36
Figure 36: The extruded dome body ........................................................................................................... 36
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Figure 37: The bottom dome after hollowing the inner part to form a shell ............................................. 36
Figure 38 :The rudder side sketch .............................................................................................................. 36
Figure 39: Rudder after extruding the sketch ............................................................................................. 36
Figure 40: The top dome cover sketch........................................................................................................ 37
Figure 41: The sketch of the top dome after extruding .............................................................................. 37
Figure 42: The sketch of the undesired part to be removed ...................................................................... 37
Figure 43: The top dome after cutting and chamfering.............................................................................. 37
Figure 44: The top dome after hollowing the bottom surface ................................................................... 37
Figure 45: Fluid domain Box (dimensions) .................................................................................................. 38
Figure 46: transfer options for inserting a body ......................................................................................... 38
Figure 47: The body after inserting it into the fluid box ............................................................................. 38
Figure 48: The Body (Void) and the Fluid (Solid) ........................................................................................ 38
Figure 49: The flow stream lines in the submarine hollow interior ............................................................ 39
Figure 50: Isometric view of the velocity streamlines ............................................................................... 39
Figure 51: Drag coefficient for different shapes ......................................................................................... 40
Figure 52: This figure illustrates the similarity between the submarine and the streamlined body shape40
Figure 53: The relation between the Breadth and the Depth of the software .......................................... 41
Figure 54: The analysis systems of ANSYS .................................................................................................. 42
Figure 55: inserting the geometry to the FLUENT ...................................................................................... 42
Figure 56: The generating to upload the geometry ................................................................................... 42
Figure 57: The geometry after uploading to the design modeler .............................................................. 42
Figure 58:Meshing initiation ....................................................................................................................... 43
Figure 59: Mesh options and naming selections ....................................................................................... 43
Figure 60: Body after meshing .................................................................................................................... 43
Figure 61: The figure below is a zoom in on the submarine flap to visualize the fine mesh. ..................... 44
Figure 62: This figure demonstrates the shape and the number for partitions ......................................... 44
Figure 63: Setting up thesimulation ............................................................................................................ 45
Figure 64: The vehicle body wall conditions ............................................................................................... 45
Figure 65: Velocity inlet parameters and conditions .................................................................................. 45
Figure 66: Outlet parameters and conditions ............................................................................................. 45
Figure 67: Surrounding wall Conditions ...................................................................................................... 45
Figure 68: Simulation monitor for drag and lift .......................................................................................... 46
Figure 69: Scaled residuals .......................................................................................................................... 46
Figure 70: Side cross-sectional view of velocity streamlines ...................................................................... 47
Figure 71: Tail cross-sectional view (streamlines) ...................................................................................... 47
Figure 72: Tail top cross-sectional view (streamlines) ................................................................................ 47
Figure 73: side cross-sectional view of velocity vectors ............................................................................. 48
Figure 74: Top cross-sectional view of velocity vectors.............................................................................. 48
Figure 75: Turbulence at the bottom camera dome .................................................................................. 48
Figure 76: Turbulence at the top fin ........................................................................................................... 48
Figure 77: pressure contour (isometric view) ............................................................................................. 49
Figure 78: pressure contour (Face view)..................................................................................................... 49
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Figure 79: Pressure contour in the hollow interior ..................................................................................... 49
Figure 80 Pressure contour lines (Transparent body) ................................................................................ 49
Figure 81: Forces at the Z axis (the driving axis) ......................................................................................... 50
Figure 82: Forces at the Y axis (the axis vertical to the body) .................................................................... 50
Figure 84: The Inlet diameter of the Submarine ......................................................................................... 53
Figure 83:The picture shows the length of the submarine ......................................................................... 53
Figure 85 : The picture shows the outer diameter of the submarine ......................................................... 54
Figure 86: The picture shows the length of the fin which is equal in both sides (right and left) ............... 54
Figure 87: The picture shows the length of the dorsal fin .......................................................................... 55
Figure 88: The picture shows the height of the dorsal fin .......................................................................... 55
Figure 89 : The picture shows the total length from one side wing of the submarine to the other side ... 56
Figure 90: The picture shows the length of the side fin (wing) .................................................................. 56
Figure 91 : The picture shows the width of the back fin ............................................................................. 57
Figure 92: The picture shows the length of the back fin ............................................................................ 57
Figure 93: The picture shows the length of the place where the flash light and the camera will fixed ..... 58
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Abstract
This project is a solution to an actual problem that has been given to us by the Oil spill response
company, where they face problems in inspecting the seabed after an oil spill accident occurs.
Usually, some of the oil that gets emulsified with sea water it sinks to the sea bed and
contaminates it. The company usually sends divers to inspect, but this process is very slow.
Therefore, the company requested a submersible surveillance vehicle that can be towed by a
boat.
As a result, we needed to design a submarine that must be remote controlled, simple, light
weighted, strong, hydrodynamic and efficient. Many designs and sketches were carried out to
try to come up with several options before choosing the suitable one with respect to the
anticipated environment. After that, we started eliminating options that were over complicated
or inferior.
The final chosen project is a submarine vehicle that is equipped with camera and flash lights to
monitor the seabed. This submarine is towed by a boat using a steel cable, where this cable
can be fed up to 40 meters depth not length. The submarine will have a remote controlled
rudder and flap to control its vertical and lateral maneuvering. Powerful flash light will be
installed to the bottom of the submarine to shed light on the seabed. All the electronics and the
electrical devices must be waterproofed and can withstand high water pressure.
The project includes the building of a prototype, it was also tested in small water tank and the
results were a satisfactory. In addition, the cost of this project is about 300 BHD.
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Summary
The objective of this project is to design and manufacture a towed submarine with a surveillance camera
which have to marine up to 40 meters depth. This project will help the company to develop their
equipment that deals with cleaning the oil from the sea. The project should be accomplished at the end
of this semester which is about 12 weeks and it will contain a prototype that used to simplify the
concept of how the project will work. Moreover, proposed designings, Solid works and hydrodynamics,
Material selections, Accessories installation and Testing are the main steps that need to be carried out
to finish the project.
The selected project was a towable submarine with a surveillance camera and that project was finally
chosen after it discussed with the polytechnic supervisor. The goal of this project is to solve the problem
which faced the company to find the places where the oil deposits after it leaks from the ships.
Moreover, it was selected because it gathers the needs of knowledge in theoretical and practical
experience that have been given in the previous semester. Furthermore, it was the most interesting and
challenging project rather than the other three project that given by the company.
The Oil spill Company will greatly benefit from this project, which will save them a lot of effort and time
when they start gathering the oil. In addition, it will be the important part in solving the problem that
they face in when they search for deposits of the oil after period of time. Moreover, it will be a useful
device for the inspection after they finish the cleaning process, so the company can insure that there will
be no more deposits of oil in the seabed.
Bahrain Polytechnic will benefit from this project, which will enhance and increase its reputation.
Moreover, graduate students will represent the polytechnic and expand its reputation in Bahrain and all
the countries of the world. Furthermore, they will be eligible to be part of the internal companies and
industries that required skills and understanding of the concept, coupled with self-directed learning and
these required will found in projects that have the same level of the project which will be given to the
company.
The project should be presented at the end of this semester which is 12 weeks and it will contain a
prototype that used to simplify the concept of how the project will work. The prototype will be
presented and given to the company to be testes as a new technology in order to ensure that it will be
applicable with their requirements and fulfill their needs.
The submarine project is a vehicle which fitted with camera and flash light to be suitable for the
requirement of the oil cleaning process, which is to access the seabed. The device has to reach up to 40
meters depth which is dark area and that why the flash light was installed, which will be at the bottom
of the submarine to give good lightening, so the camera can take a clear picture. Moreover, a steel cable
will be used to tow the device by a boat and this device will be controlled remotely. A remote controlled
rudder will be used to control the lateral and vertical direction of the device, motor or a hydraulic jack
will be used to control the movement.
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Research
The research consists of studies and creative work in order to expand the stock of knowledge.
This part will consist of research and studies from the internet regarding the project, starting
from geometry to the material.
Initial sketches
The beginning of any design starts by sketching or drawing ideas in mind on a paper, these
sketches are not too detailed, just a simple pencil drawing.
Sketches are very important, where they are based on research done by looking on previous
designs or other stuff that can influence the sketcher.
The submarine project started with 3 primary sketches:
The first sketch idea was taken from a submarine that
was found in internet. The shape of the submarine looks
like a rocket which has good hydrodynamic shape.
The second sketch idea was taken from a shark, where
the outer geometry looks like a shark. The shark has
great stability and maneuvering in the sea, therefore a
shark is a great choice for a submarine's shape.
The third sketch was taken from a lure used in fishing,
where the lure looks like a small fish. This fish has a good
hydrodynamic body which is required to design the project
and it is also towed.
Figure 1: The first sketch ( similar to an exixting design)
Figure 2: The second sketch idea take from (wind sovk & shark)
Figure 3 : The third sketch ( fish lure shape)
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Elimination
In this stage, the undesired sketches are eliminated due to complication or they are not good
enough.
Regarding the project, the first sketch was eliminated because the body of the submarine is
enclosed and it will require a complicated system to control the air/water ratio inside it which
controls the depth.
The third sketch was also eliminated because the lure fish is designed to dive up to a specific
depth, however it is hard to add a control system of guidance to this design.
The chosen one
The second sketch was the most suitable because of the following two reasons:
Automatic guidance
Efficient lateral control
The hollow shape provides the vehicle with automatic guidance, where the body will directly direct itself
collinearly while driving due to the fluid passing through it. This idea was taken from the windsock that
will be explained onwards.
The hollow shape of the vehicle starts wide and gets narrow gradually; this forces the fluid to accelerate
at the outlet which will provide the rudder with a great working efficiency even if it is driven at low
speed.
Bio-mimicry
Bio mimicry is a process that studies nature and then
imitates the designs of nature to solve human problems faced in their real life. As an example,
the shape of the plane was taken from the birds.
The proposal of that is nature has already answered many of the problems that faced humans
in their life. The expert engineers of the nature are animals, plants and microbes. After that,
people found what works, suitable and most important things that still here on earth. After a
lot of research and development, they found after 3.8 billion years that everything around us in
the world is the secret to survival. (What is Biomimicry?, 2007/2013) .
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Looking at Nature as Model and Mentor
Nature as model:
Bio mimicry is a new science, which is the study of the nature models. After that, by simulate
these form and strategies led to solve human problems. The bio mimicry design spiral
developed a practical design tool developed by guild and it collaborators. Moreover, they used
nature as model.
Nature as mentor:
Bio mimicry is a process to observe and assess the nature. It is based on what we can learn not
what we can extract from the nature. (What is Biomimicry?, 2007/2013) .
Shark's body
Body Shape
The body shape of the sharks is normally fusiform body
which is rounded and tapered at both ends. Moreover, this
shape is helpful because it's required minimum amount of
energy to move and swim.
Tail fin (represents the rudder):
The tail fins that the sharks have helps to move downwards and forwards due to the different sizes of
the upper and the lower side (upper side is bigger than the lower side).
Pectoral Fins (represents the wings):
Pectoral fins are located to the side of the front part of the shark where they are rigid and help passing
through the water horizontally. Furthermore, it is provided to move downward and that provide lift to
offset the tail fins.
Dorsal fins (represents the top fin):
Dorsal fin is located at the top of the shark. The stability of the shark is due to the paired pelvic fins.
Moreover, one or two dorsal fins and dorsal fin spines are also help stabilize the shark.
(Sharks Hydrodynamic).
Figure 4 : Shark body
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Windsocks
Windsocks are simply shaped as cones which attached to fixed
mounts. It was seeded into a tube shape sock material. Moreover,
due to the internal pressure inside, it makes the windsock taper
floating in the air. It is led to lift the wind cone and making wind
socks stretched out like it. However, this is only when there is wind.
Furthermore, it is used in airports, ports and chemical plants which
designed to show the direction and relative wind speed.
(How Do Windsocks Work?, 1999).
Aerodynamics
A windsock aerodynamics is intricate, but mainly it is involves on compressing. Compression is
very small, but it was enough to force the socks pulled up. As the tube becomes smaller, the
pressure and speed of the wind increases. This facilitates the socks to make it stick straight out
of the wall, and it led to have some turbulence that makes the sock flutter. While having a large
inlet and small outlet, the windsock has the ability to look like a funnel for wind. Moreover, the
sock will be inflated by increasing its velocity and force.
(How Does a Windsock Work?, 1999) .
Relation to our project
The wind sock influenced us because of its ability to align collinearly to the wind direction which is an
important requirement for the submarine (auto guidance).
Figure 5 : Wind sock
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Material selection
The process of selecting material is an important step in the way of achieving a high quality and durable
product. There are three materials that were chosen in the beginning of the material selection process.
The three following materials will be explained in details.
Aluminum
Aluminum was one of three materials that were chosen in the beginning of the
selection process for many reasons, such as;
Corrosion Resistance
The corrosion resistance of aluminum is produced naturally with a protective oxide coating. Moreover,
these properties can be improved with different types of surface behavior. For example, anodizing,
painting or lacquering. It is usually used in some application that required protection and conservation.
Ductility
Ductility and low melting point are the main properties that the aluminum has. It can be processed in
many ways under melt conditions. Its ductility makes aluminum products basically formed to be close
enough to the end of the product design.
Weld ability
The fact that aluminum is weld able is a good point, where it will ease the process of construction and
fabrication. Hence, that welding can be waterproof and strong.
(Aluminium - Specifications, Properties) .
Figure 6: Aluminum physical properties
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Carbon Steel
Carbon steel was the second choice material that was chosen in the
beginning of the selection process for the following reasons;
Strength
Carbon steel is one of the strongest types of steel which is mostly harder than iron. The reason is
because the iron is the main component of steel that mixed with other alloying materials to produce it.
(About the Properties of Steel) .
Weld ability
The fact that steel is weld able is a good point, where it will ease the process of construction and
fabrication. Hence, that welding can be waterproof and strong.
(Materials Selection for Corrosion Protection Seawater) .
Properties Steel
Density (1000 kg/m3) 7.85
Elastic Modulus (GPa) 190-210
Poisson's Ratio 0.27-0.3
Thermal Expansion (10-6/K) 9.0-15
Melting Point (C)
Thermal Conductivity (W/m-K) 26-48.6
Specific Heat (J/kg-K) 452-1499
Electrical Resistivity (10-9W-m) 210-1251
Tensile Strength (MPa) 758-1882
Yield Strength (MPa) 366-1793
Percent Elongation (%) 4-31
Hardness (Brinell 3000kg) 149-627
Table 1 : Steel physical properties
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Fiber glass
High Strength
High-strength fiberglass requires a high strength weight ratio and minimum weight
to males it an excellent material. Textile form, it allows the design to be flexible and low cost due to the
strength that can be unidirectional or bidirectional.
Chemical Resistance
Fiberglass does not have any effects from most chemicals. Moreover, hydrofluoric, hot phosphoric acids,
and strong alkaline substances are the only chemicals that affect the fiberglass and these chemicals will
not be seen in seawater, so it will be hard to
destroy the fiber.
(Fiberglass) .
Property Minimum
Value (S.I.)
Maximum Value (S.I.)
Units (S.I.)
Density 2.55 2.6 Mg/m3
Compressive Strength
4000 5000 MPa
Ductility 0.026 0.028
Elastic Limit 2750 2875 MPa
Hardness 3000 6000 MPa
Poisson's Ratio 0.21 0.23
Shear Modulus 30 36 GPa
Tensile Strength 1950 2050 MPa
Young's Modulus
72 85 GPa
Table 2: Physical properties of fiber glass
Environmental Properties
Resistance Factors (1=Poor 5=Excellent)
Flammability 5
Fresh Water 5
Organic Solvents 5
Oxidation at 500C 5
Sea Water 5
Strong Acid 5
Strong Alkalis 4
UV 5
Wear 5
Weak Acid 5
Weak Alkalis 5 Table 3 : Environmental properties of fiber glass
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Selection process
The three materials above were chosen due to some advantages for each of them. In addition, one of
them was selected for the submarine. The materials were discussed why they chosen for this project
and why we choose one of them as a final material.
First of all, fiberglass was chosen as a final material because of its properties and the suitable
specification required to be used in sea water. It was selected due to its strength, corrosion and
chemical resistance. Fiberglass is easy to be shaped on any model you build and the process of doing
that was discussed in the previous part. Moreover, we take an advice from Dr. Kealan about it and he
said that it will be useful to use it rather than aluminum and steel.
Steel is a good materials to use but in our case it will be useless because it will be too heavy and it is not
a corrosion and chemical resistance where we deal with oil and sea water. In addition, aluminum is also
worthless because when we deal with depths in the seas, it is not strong enough to bears the high
pressure.
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Product Design Specification
Budget
There is not specific budget limited for this project, but this project will be built with high quality and
with minimum cost possible. This budget must cover all the materials, accessories, tools and any other
parts related to this project.
The projects building material is fiber glass, its the same material used for boats.
Manufacturing facilities: The fiber glass can't be made at the university workshop; therefore we will
have to give the design to a company that will be able to build the prototype. There are many fiber glass
companies locally such as; Yamal Fiber glass, Al Durazi, Al haramain and many more. Further assemblies
will be performed in the university's workshop.
Project accessories: The accessories that will be installed to the project such as, water proof remote
controlled camera, sensors, electronics, motors and other minor or major parts will cost around 200
BHD approximate.
Equipment in the workshop
The table.4 shows the equipment that are
available at the workshop currently, where this
number can change due to any break down or
usage by other groups or individuals. This major
point must be in account to avoid slowing down
the building process. Therefore, to avoid
wasting time we must not wait for the
equipment to be free but to start something
else that is available.
The big tool box consists of hand tools such as;
Screw driver, Cutters, spanners, drill bits, measuring tapes, rivet gun, claps, Allan keys, jig saw, rulers
and many other tools.
Equipment Available quantity Milling machine 2 Lathe machine 2
MIG welding machine 2 TIG welding machine 2
Tube bender 1 Small crane/lift 1
Vice 6 Tool box (big size) 2
Tube notcher 1 Metal chop saw 2
Angle grinder 3 Drilling machine 1
Table 4 : Equipment available at the workshop and quantity
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Time The estimated time to finish this project is based on an assumption, where this assumption is the best
case scenario. In this scenario we assumed that:
No causalities or accidents will occur to any member of the group,
Materials will arrive on time,
Availability of all the tools required,
Accessories and electronics will arrive on time,
The polytechnic supervisor is present for assistance.
Working hours:
The work will be divided into self-directing hours and workshop practical hours.
The amount of hours per week = 7 hours of self-directing 7, multiplied by 10 which is the number of
weeks = 70 hours per person.
Number of people in the group: 2
Total working hours: 140 hours
Date on which started: 23rd of September 2013
Date on which expected to finish: 5th of January 2013,
Final submission deadline: 2nd of January 2013.
Safety It is very important for any product to assure and protect the safety of the user. The submarine vehicle must be light in weight where it will be unloaded of the boat and loaded back in by users, therefore any heavy weight might injure their back or pull them off the boat. Another thing that must be taken into consideration is to chamfer any sharp edges to avoid causing cuts to the users that will lift this vehicle. Adding a couple of handles will help avoiding injuries and provide an easy grip.
Knowledge and industrial skill: The current graduation project will require theoretical and practical skills that were gained during the past 3 years of Mechanical engineering degree. There are some courses and knowledge that we think we will require the most in designing and building this project, such as:
Manufacturing mechanical parts, Mechanical practical experience, Engineering design using AutoCAD, Solid Works and ANSYS 14.0, Fluid mechanics, Technical report writing skills and vocabulary, Engineering mathematics, Engineering mechanics, Material selection, Engineering computation.
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Environment
This submarine will be used by the oil spill company in Bahrain; therefore it has to be built with respect
to the Arabian Gulf sea specifications.
The Arabian Gulf is an enclosed area of water with high rates of evaporation due to the high
temperature in this region. This evaporation increases the salt rates in this sea, with low flow of sea
water from the Strait of Hormuz and the input from the Rivers Tigris and Euphrates.
Table.5 will illustrate the properties of the seawater of the Arabian Gulf (sample taken from Abu Dhabi):
Constituents Arabian gulf
( Abu Dhabi)
Chloride 24 300 Sulfate 3 420
Bicarbonate 200 Sodium 13 900
Magnesium 1 560 Calcium 600
Iron 0.3 Total dissolved solids 43 980.3
pH 7.8
Specific gravity 1.029
Temperature 'C 23
Table.6 to the right shows the comparison between the
sea water, spring water and tap water.
All these information must be taken into account before
selecting the materials that will be exposed to this
environment. (Brown).
Table 5 : The properties of the Arabian Gulf sea water
Measurement Sea Water
Drinking Water
Temperature 'C 23 23 Specific gravity 1.029 1.002
Salinity and NaCl 5.0 0.3 pH 7.80 7.00
Table 6 : Comparison between the sea water and drinking water
Figure 7: The Arabian Gulf map.
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Design and Manufacturing
The process of designing
The diagram above illustrates the steps that are followed in the designing process of our submarine. The initial phase started by an ideas and needs, where many sketches and ideas were drawn and documented. After that, the research phase was carried out by surfing the internet through websites, articles or pictures that are important and can improve our initial designs. Tutors were also a main part of our research phase, they didnt answer us directly but they would direct you to the correct path. Next, the concept phase starts by eliminating all the over complicated or unwanted designs and keeping the most suitable one. This suitable design is now our concept. Subsequently, this concept is drawn in more details as a draft and wait for the supervisors approval to model it using software. Later, in the model design phase the preliminary design will be sketched in detailed engineering drawing using SolidWorks software. This drawing will consist of dimensions, 3D view of the design and much more details. Afterward, before the manufacturing phase starts the materials that are required to produce the submarine must be listed and ordered based on the engineering drawings. Finally, the construction phase starts after the arrival of the materials.
Design software: Solid Works and Computational Fluid Dynamics.
Communication
The weekly reporting method
The weekly reports are written individually by each member to show the tutors and supervisors of the responsibilities and duties done every week. The communication between the two members of our project is by having a fixed day every week to discuss what have been finished and what problems do we face. However, there is also a specific day every week where we have a meeting with our supervisor to update him with our status and consult him
Figure 8: This figure illustrates the product cycle bubble map. (Product cycle ).
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if we are facing any problems regarding the project. Each member of the group is allocated with specific parts to work on, these parts has been distributed by the approval of the members and the supervisor. This methodology assists members in managing their time on a weekly basis. Responsibility assignment matrix
A responsibility assignment matrix (RAM) is a table that shows the distribution of work on the group members and what are their roles and responsibilities.
Milestones
Managing the project, time-wise and cost-wise, Choose the best material for the body work, with keeping the availability and processing tools
availability under considerations, Constructing the submarine framework similar to the dimension from the engineering drawings, Purchase the accessories and electrical components. Example: Camera, Flash light, electric
motors and sensors. Assembling and finalizing the minor parts.
Deliverable Task Ahmed Aziz
General research and gathering information Internet websites
x x
Design process
Initial sketches
x x
Detailed 3D Solid Work modeling
x x
Fluid Simulation Ansys simulating x -
Prototype construction Solid works 3D printing
x x
Mathematical calculations Forces x x
Time management x x
Prepare final proposal report and division of work Assemble report and present final idea
x x
Table 7: This table shows the tasks and responsibilities of the two group members.
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Function
Weight The weight of the submarine is a major consideration, where it should be as light as possible. The fact that people will lift this vehicle to unload it to the sea or load it back to the boat is serious. The framework must be strong to withstand pressure but in the same time it must be light to be easily carried. Weight of the vehicle: 50 Kg using SolidWorks
Chassis material: Fiber glass
Submarine Dimensions
Length
1 m
Width
0.5 m
Table 8: Submarine dimensions
Figure 9: The submarine body sketched by SolidWorks
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Basic structure
The structure of this project is divided into 5 main parts:
Casing or Body,
Flaps,
Rudder,
Top dome,
Bottom camera dome.
Figure 10: The body of the vehicle
Figure 12 : The rudder is a very important part, where is provides the vehicle with lateral movement
Figure 11: The top dome is where electronics and flash light will be installed and protected from water.
Figure 14: The flaps are also very important parts, where they control the vertical movement of the
vehicle. Figure 13: The bottom dome is where the
camera will be installed; the material of this part must be clear plastic.
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Installations
This vehicle will be equipped with electrical systems; these electrical systems will be powered with a battery. Voltage: 12 volts (standard battery) Amps: the amount of amps depends on the electrical parts requirement. The following components will be installed to the vehicle; their value of amps will be added to get an approximate value. Water proof camera: 7.5W Since, I (A) = P (W) / V (V) 55W/12V: 0.625 Amps.
Remote controlled rotating pan: 10W Since, I (A) = P (W) / V (V) 10W/12V: 0.83 amps
Flash light: 5W Since, I (A) = P (W) / V (V) Two flash lights to be used So, 5W/12V: 0.4 x 2= 0.8 amps
Flap motors: 20W Since, I (A) = P (W) / V (V) so, 20W/12V: 1.6 Amps. The total amount of amps = 4 amps. There are batteries that could supply 12.5 Volts and 4.5 amps in the local market.
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Planned Preventive Maintenance
Planned maintenance is highly recommended for this vehicle. This plan will help avoiding any problem or malfunction from occurring in the future. This maintenance will be carried out to guarantee that the vehicle is operation properly.
Checklist Action
Cleaning the submarine
The vehicle body must be cleaned from sea water every time after finishing from usage.
Remote controls
The remote control must be inspected before using to prevent facing problems with
guidance.
Camera
Camera lens must be cleaned before loading it to the sea for a clear view.
Flaps and Rudder
The flap and rudder motor must be inspected and maintained every time before and after the process.
Steel cable and
pivots
Have it checked occasionally. The pivots must be well welded and the steel cable
must be safe without any cuts to avoid losing the vehicle due to any collision.
Battery
The battery must be charged every time after it has been used to prevent losing the
control of the maneuvering.
Table 9: This table shows the plan to prevent the vehicle from failures.
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Fiberglass
Fiber glass or also known as glass reinforced plastic is a strong and lightweight material. The physical
properties such as strength and weight are favorable when it is compared to other metals. In addition,
the fiber glass is an easy forming material and it can be formed using molds. Fiber glass has high
resistance to moisture, where it doesn't absorb moisture and doesn't change physically or chemically
when it is exposed to water. (Fiber glass) .
The table above illustrates the different types of fiber glass and its properties. The highlighted row is
the type that is commonly used in Bahrain and is available locally. The Polyester and Chopped Strand
Mat is the material used in building fishing and sports boats and other sea vehicles. (Fiberglass &
Composite Materials: An Enthusiast's Guide to High Performance Non-Metallic Materials for Automotive Racing and
Marine Use., 1 April 1996. ).
Material Specific gravity
Tensile strength MPa
Compressive strength MPa
Polyester resin (Not reinforced) 1.28 55 140 Polyester and Chopped Strand Mat Laminate 30% E-glass
1.4 100 150
Polyester and Woven Roving Laminate 45% E-glass
1.6 250 150
Polyester and Satin Weave Cloth Laminate 55% E-glass
1.7 300 250
Polyester and Continuous Roving Laminate 70% E-glass
1.9 800 350
E-Glass Epoxy composite 1.99 1,770
S-Glass Epoxy composite 1.95 2,358
Table 10: This table illustrates Fiber glass types and properties.
Figure 15: Fiber glass application
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Testing
Testing the prototype is an important step before testing it in the sea, where all the electric and electronic parts and devices must be tested. The flap's and rudder's motor must be tested to ensure if it's powerful enough to steer underwater. Visual testing and inspecting is also important, some errors can be discovered visually while the others will be discovered while functioning in the sea. Before giving a final approval, the Following points must be checked and kept under consideration:
Satisfied tolerance values,
Drag force,
Buoyancy,
Sinking weight.
The sinking weight will be added after the submarine is in the sea, where the amount of weight added must pull the submarine exactly under the sea surface, knowing that the body that is made of fiberglass and foam floats. The vehicle must be under the sea surface so its flaps and rudder can function.
Finally, the submarine prototype will be tested in the sea, where it will be towed by a boat and all its functions must be tested to ensure that everything is working properly.
Customers and sponsor
Our customer: Mr. Richard Sims, Oil Spill Regional manager Our sponsor: Bahrain Polytechnic
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Construction process
There are several steps that will be used to make sure that the fiberglass is well used. Before begin in
the process, some preparations must be consider:
Having the model of the project which will be used as a guidance to coat it with fiberglass and
have the final shape.
Clean the model from dust and dirt.
By using sand paper to clean the surface and have best result will using fiberglass.
The following steps are used for applying fiberglass to a boat and it will be same concept using it the
model of our project:
1) At first, mix resin and hardener in a paint tray. Wait for about 30 minutes to have the best mixture
that will be ready to apply to the model.
2) Use a foam roller (same as the picture below) to put the first coat. This coat known as the seal coat.
Spread the coat on the model equally as possible.
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3) After adding the first coat, the fiber glass must be ready to apply on the model. By cutting the
fiberglass to the shape needed, its help to be fit without any gaps. After that, fix the fiberglass to the
model using tape or staples.
4) After fixing the fiberglass, wait for it to get hard and then clean the surface and make it tidy with a
grinder or sand paper depends on the hardness of the fiberglass.
5) Next, applying another coat of resin which is called the bond coat. The material used to attach the
fiberglass on the model (tape or staples) must be removed before adding the second coat
completely.
6) After the two coated of resin, a final coat has to be applied. It should be smooth and thick enough to
make sure that when using a sand paper it will not damage and affect the fiberglass.
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7) Wait for the final coat to dry, better to be overnight. After that, sand it at first using lower grit and
finish it with a higher grit for better results.
8) At the end, paint the model with a protective marine paint. (Fiber-glass-building)
Fiberglass
Fiberglass is an extremely flexible and useful material which comes in different shapes.
Moreover, most of people see the fiberglass insulation and how its affect the skin of the body
when touching it. It's because of the tiny pieces of glass cut and goes into the skin which causes
itchy feeling and irritation.
Resin and Hardener
Fiberglass will not work without resin and it will be ineffective for using it with anything
required rigidity.
Moreover, before using the resin in any purpose to the fiberglass, it has to be mixed with
catalyst which is called hardener. In addition, the mixture between the resin and the hardener
will cause a chemical reaction which led to produce heat. The heat depends on the quantity of
the resin mixture which makes it quit hot to melt plastic. (Fiber Glass).
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Solid works SolidWorks is program that is used by designers to draw 2D or 3D designs. This program is a computer-
aided design that is developed by Dassault Systems that is used to convert idea into great products and
is mainly used by engineering and designers all over the world. ( "Technical Alerts & News") .
The sketching of the project starts by drawing the skeletal parts or the main parts. Firstly, we start by 3D
sketch on the front plane and from the origin point.
To draw the submarine body, 3 circles must be draw at equal
spacing where they form the body. After that these circles are
connected by four splines where they are the guide lines to
extrude the body; as shown in the figure to the right.
The following feature is then used to extrude the body from
the sketch above to give the following result.
As shown in the figure below.
Figure 16: This figure demostrates the initiation of the sketch on the front plane
Figure 17: 3D sketch of the submarine outlines
Figure 18: Lofted body of the vehicle
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After finishing from the body, the flaps were sketched on a 2D sketch to one side of the body and were
then extruded using the boss extrude feature. The fillet feature is then used to apply a smooth edge to
the wing face.
The same procedure was also done to form the top fin
of the submarine as shown in the figure to the right.
After finishing with the right wing, the feature is then
mirrored to the other side using the mirror feature and
choosing the right plane which passes along the center of
the body.
Figure 19: Wing sketch
Figure 20: Flap after extruding feature and chamfering the front edges.
Figure 21: The top fine sketch
Figure 22: The submarine body after extruding the top fine and the wings, where the flap was mirrored to the
opposite side.
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Next, the rudder pivots were sketched and extruded at the rear end of
the body. These pivots are the contact point where the rudder will be
joined.
After extruding the feature was then mirrored to the bottom side as
shown in the figures below.
The top dome's base was sketched and then extruded as shown in the following figure.
Figure 23: Rudder's pivot sketch
Figure 24: Pivot body mirrored Figure 25: Mirroring pivot features
Figure 26: Top dome sketch, before extruding
Figure 27: Top dome after extruding
Figure 28: Bottom dome, where the same procedure of the top dome was repeated for the bottom.
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Following, the submarine body was hollowed from the
inside using the cut loft feature.
Before using the cut feature, the circles and guide lines
that the feature will use must be sketched. The same
basic drawing used in the beginning of the sketch was
used but with an internal offset of 2 mm. The result is
shown in the figure above.
Next, the cowling is sketched on a 2D plane as shown in
the figure to the right. The cowling is the vehicles cover
that is added to reduce the drag force on the body.
After sketching, revolve bass feature was used to rotate
the feature around the circular face to form the cowling as
shown in the figure below.
Figure 29: the submarin body after hollowing the inner part
Figure 30: The sketch of the cowling.
Figure 31: The cowling after revolving the sketch
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The next step is to start adding more detailed features, firstly we start by removing the flap part of the
wind by sketching on the wing a rectangle shape and using the cut extrude feature to remove it.
The figure below shows the result after removing the part where the flap will be installed. This feature
was then mirrored to the other
wing to ease the process.
After that, the rear wings were sketched on a 2D plane and
extruded towards to body as shown in the figure to the right.
The next step is to cut the extra part by sketching an arc on the
top of the rear wing and use the cu extrude feature to form the
following result as shown in the figure below.
Figure 32: The wing after cutting the flap part.
Figure 33: The extruded rear wing
Figure 34: The rear wing after cutting feature
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In this step, the bottom dome cover will be formed by
sketching the shape of the dome and then extruding it
using the boss extrude feature as shown in the following
figure.
After that the shell feature was then used to empty
inner part of the extruded body.
Next, the rudder was sketched using splines and lines to draw the outer shape of the rudder (side view).
Then, the boss extrude feature is applied to form the rudder as shown in the figure below.
Figure 35: The sketch of the bottom dome cover
Figure 36: The extruded dome body
Figure 37: The bottom dome after hollowing the inner part to form a shell
Figure 39: Rudder after extruding the sketch
Figure 38 :The rudder side sketch
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The last step, the top dome was sketched on a 2D
plane by taking the dimensions from the base on the
submarine body. This sketch was then boss extruded
up to 50mm. Then sketching on the side view, this
sketch was the cut extruded.
This step was done to give a smooth hydrodynamic
surface to the top dome.
Finally, the corners were smoothened using the
fillet feature and hollowed using the shell feature.
Figure 40: The top dome cover sketch
Figure 42: The sketch of the undesired part to be removed Figure 41: The sketch of the top dome after extruding
Figure 43: The top dome after cutting and chamfering
Figure 44: The top dome after hollowing the bottom surface
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Figure 45: Fluid domain Box (dimensions)
Figure 46: transfer options for inserting a body
Preparing the model for Ansys simulation
First of all, the model must be prepared to be inserted
to the ANSYS program. To ease the process of inserting
the geometry and meshing it in the program, the
model must be simplified by sketching the fluid
domain as solid (Boss Extrude) and the submarine
walls as air (void).
The size of the fluid domain must be large enough to
place the whole model into it; the size of the domain is
(1.5m x 1.5m x 4m).
After extruding the fluid domain, the submarine body is inserted into the box
by dragging it into the new drawing (fluid domain sketch), and choose the
inserted body (submarine) as derived part. The program will give transfer
options of the model; however the only option needed is the 'Solid Body'.
Next, click the "Green Tick" sign to insert the body directly into the origin
center, which is the center of the fluid box.
If a problem was faced regarding the position of the model;
Insert>Features>Move/Copy, then choose the body that is to be moved or
rotated.
Finally, go to Insert>Features>Combine and choose the operation
type as "Subtract", the Fluid box as "Main Body" and the
Submarine as "Bodies to Combine". The figure below shows the
result of the Combining feature.
Figure 47: The body after inserting it into the fluid box
Figure 48: The Body (Void) and the Fluid (Solid)
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SolidWorks FloXpress Report
SolidWorks FloXpress is a first pass qualitative flow analysis tool which gives insight into water flow inside the SolidWorks model. Model: Model Name: Inner submarine shell Fluid:
Water
Type Volume Flow Rate
Faces Big inlet and small outlet
Value Velocity Rate: 2.00 m/s
Environment Pressure 1
Type Environment Pressure
Faces Big inlet and small outlet
Value Environment Pressure: 494000 Pa
Results
Name Unit Value
Maximum Velocity m/s 7.00
This flow simulation was performed to determine the velocity at the outlet of the submarine. The inner shell was firstly designed similar to a wind sock which automatically steers collinearly to the wind even if the wind speed was low; where the fluid accelerates due the change in the cross sectional area. The second idea came from the venture meter that has the same concept of increasing the fluids velocity. The importance of this simulation is to know whether the velocity is high enough to steer the vehicle for laterally. The outlet velocity is nearly four times more than the inlet, which means that the rudders efficacy is tolerable.
Figure 49: The flow stream lines in the submarine hollow interior
Figure 50: Isometric view of the velocity streamlines
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Drag force
The drag forces on any object the force that is produced by the friction between the objects surface and the fluid. In other terms, it may be known as the resistance of moving through any fluid. (Batchelor, (1967)) .
The main factor that affects the drag force is the drag coefficient; this coefficient is a unit less number that varies from one shape to another. Furthermore, the drag force increases as the objects velocity, size and fluid density increase. Some object relies on the Reynolds number and the dimensions of the object, but some objects dont rely on them. ( Drag Coefficient) ,(Shape Effects on Drag ) .
The following is a fluid dynamic equation that is used to determine the drag force of an object moving through a fully enclosing fluid.
Fd: The drag force (N),
: Fluid density(1000 kg/m3 ),
V: Velocity, A: Area,
Cd: Drag coefficient.
The area varies on which type of drag coefficient is used, where in automobiles the frontal face area is chosen. However, for submarines the reference area is the wetted surface. The towing boat will be running by a speed of 2 to 3 knots, which are 1 to 2 m/s. The drag force for the submarine can be calculated by assuming that the vehicle is very close to the streamed line body. Cd: 0.04 V: 2 m/s A: 2.1 m
2
: 1000 kg/m3
The total wetted area was calculated using area wizard tool in Solid Works. After using the equation above, the drag force is equal to = 190 Newton.
Figure 51: Drag coefficient for different shapes
Figure 52: This figure illustrates the similarity between the submarine and the streamlined body shape
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Ansys Workbench
Ansys is multipurpose software that is mostly used to simulate interactions of all disciplines of structural,
vibration, fluid dynamics and much more for engineers.
Ansys enables the user to simulate 3D or 2D tests, where it provides the user with the ability to test the
prototype in a virtual environment before production. Furthermore, it helps in determining the weak points
and foreseeing problems.
This software can either draw the structure or import it from other different engineering software that is
compatible. (Ansys) .
Fluent is a part of Ansys Workbench, this program is a very flexible and general purpose computational fluid dynamics (CFD). CFD is the science of studying fluid flow which uses numerical process to solve mathematical equations. This program provides the user with various details about forces, graphics and animation of streamline, pressure contours and much more. (Ansys Fluent) .
The results generated by the program are used in new ideas and designs, developing a product, troubleshooting or redesign an existing product.
Figure 53: The relation between the Breadth and the Depth of the software
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Inserting the geometry
First of all, the type of fluid flow software must be chosen from the analysis systems toolbox. The one that will be used for this simulation is FLUENT (as shown in figure.50). To start off with this software there are 5 steps to reach the results, these steps are:
Geometry,
Mesh,
Setup,
Solution,
Results.
Geometry
The geometry step starts by inserting the CAD file that is made by SolidWorks, follow the steps below: Right click on geometry and insert geometry (as shown in the figure below),
Click generate to covert the CAD file into a Design modular file (as shown in figure.52), Close the window and go back to the home back.
Figure 54: The analysis systems of ANSYS
Figure 56: The generating to upload the geometry
Figure 55: inserting the geometry to the FLUENT
Figure 57: The geometry after uploading to the design modeler
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Mesh
Meshing is the task of dividing a body into simple geometric elements such as tetrahedrons in 3D and
triangles in 2D. Meshing is a critical aspect of simulation, where it has a significant impact on the quality
of the results and CPU time required. There are several types of mesh as uniform and un-uniform,
structured and un-structured or hybrid grids. The un-uniform is the mesh type that is used in the
project,
Mesh is performed so that the solver can calculate various equations as
the model is finitely partitioned into simple shape. (Meshing) , (Ansys
Meshing) .
This step starts by double clicking on mesh to initiate.
After that, left click once on the mesh and go down to the details of inlet
to adjust the size required.
The mesh properties used for the project are:
Relevance center: Coarse,
High smoothing,
Minimum size: 0.0022 m,
Maximum Size: 0.45 m,
Growth rate: 1.2,
Tetrahedron and triangular meshing.
Next, click on generate mesh to finalize the meshing where it
might take a couple of minutes.
Finally to finish this step, named selections must be applied by choosing faces and naming them as
shown in the figure to the right.
The named selection assists the program to recognize
the inlet, outlet, body, and the walls.
Now close the window and right click on the mesh step
and choose Update.
The figure to the right shows the domain after the
meshing process.
Figure 58:Meshing initiation
Figure 59: Mesh options and naming selections
Figure 60: Body after meshing
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The Following figures illustrates the meshing
on the project body, where the meshing in
un-uniform. This type of meshing will use the
minimum size in curvatures and small areas
to result in an accurate simulation.
Figure 62: This figure demonstrates the shape and the number for partitions
Figure 61: The figure below is a zoom in on the submarine flap to visualize the fine mesh.
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Figure 63: Setting up thesimulation
Setup and solutions
This step is about setting options and operating conditions.
To start off, we need to check the mesh and report quality to
ensure that the mesh is tolerable.
After that, we jump directly to the materials where the H2O
liquid will be added to the materials by selecting it from the
FLUENT database.
Next, the ell zone condition is where the interior part of the domain is chosen as water liquid and the
operating pressure is changed to 494 Kpa which is the pressure under 40m under sea (desired by the
company).Then, the boundary conditions are chosen to be adjusted.
The inlet, outlet, body and wall were adjusted as seen in the following figures:
The inlet was chosen as velocity inlet with a speed of 2m/s
absolute. The wall was chosen as moving wall with an absolute
speed equal to the inlet and in the Z axis. The outlet was
chosen as a pressure aoutlet and the backflow direction
specification method was chosen as From neighbour cell to
get the reading of pressure from the cell before.
Figure 64: The vehicle body wall conditions Figure 65: Velocity inlet parameters and conditions
Figure 67: Surrounding wall Conditions Figure 66: Outlet parameters and conditions
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After that, we jump to the solution monitors, where Drag and lift
will be monitored.
Create>Drag and choose the body then tick the Plot and Write and
choose the force vector of the drag by entering 1 in the entire
three axis. This will enable the software to calculate the drag force
during calculations.
Following, head to run calculations and choose 500 iterations as
an initial trial and click calculate.
Finally, the solution converged after 245 iterations.
The iteration is a repetition process of solving an equation frequently until it reaches a desired value.
The scaled residuals plot shows the value versus the number of iteration and when the value reaches a
specified tolerance.
Figure 68: Simulation monitor for drag and lift
Figure 69: Scaled residuals
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Results
Velocity Streamlines
This part includes the velocity magnitude
formed in lines that shows how will the water
pass through and around the submarine. The
first figure shows that the water slows don
slight in front of the submarine and keeps
slowing as it enters. This reduction in speed is
due to the cone shape of the vehicle, where the
water slows down in the larger cross-sectional
area and increases to the maximum velocity at
the exit.
The streamline proves that the vehicle is a
hydrodynamic body.
Figure 70: Side cross-sectional view of velocity streamlines
Figure 71: Tail cross-sectional view (streamlines)
Figure 72: Tail top cross-sectional view (streamlines)
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Velocity Vectors
The velocity vector illustrates the speed and
the direction of water as it collides with the
vehicle, this will show the parts that causes
turbulence.
The first figure assures what was
mentioned before that the velocity
increases up to 2.75 at the exit which are
colored in red.
The velocity that is close to the body
decreases slightly due to the body friction,
therefore these results are reasonable.
The two figures below are focusing on the turbulence caused by the geometry. First of all, the top fin
causes some turbulence behind it because of the edge.
Secondly, the bottom casing where the camera and flash light will be installed is creating turbulence
because of the poor its geometry. The angle is very high and flat to the stream.
Figure 73: side cross-sectional view of velocity vectors
Figure 74: Top cross-sectional view of velocity vectors
Figure 75: Turbulence at the bottom camera dome Figure 76: Turbulence at the top fin
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Pressure contours
The pressure is a continuous force exerted on
the submarine that is in contact with the
water. As seen in the following figures, the
parts that face the stream has high pressure
contoured in red. While the rest of the body
has normal or decreases pressure because it
doesnt face the stream.
Looking at the cross-sectional view, it shows
that the pressure at the inlet is higher than the
outlet which makes sense. This is because; the
narrowing of the internal cross-sectional area
of the vehicle forces the stream to increase
Where 'Bernoulli's Principle' states that (an
increase in velocity causes a decrease in
pressure at the point of restriction').
Figure 77: pressure contour (isometric view)
Figure 78: pressure contour (Face view)
Figure 79: Pressure contour in the hollow interior
Figure 80 Pressure contour lines (Transparent body)
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Forces
The two forces that were monitored during this calculation are the drag and lift forces.
Z Axis
The following figure shows the drag force provided by the software:
Loking t the figure above, the total force acting on 'z' direction is equal to 256 newtons, and the neative sign define
the direction which is opposite to the driving direction. The theoretical drag force that was calculated previously in
the report is equal to 190 Newtons. The difference between the two results is 25% which might be an error of
assuming the drag coefficient shape.
Y Axis
The following figure shows the lift force that is also calculated by the software, the valuse of the lift is in negative
which means that the vehicle is being force downwards, this is a good result where the sbmarine must dive in
slighlty as the towing starts.
Figure 81: Forces at the Z axis (the driving axis)
Figure 82: Forces at the Y axis (the axis vertical to the body)
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Discussion
This part will explain several points regarding our project from difficulties we faced to the benefits of the project on us. In the beginning, the project was a new idea to us from different views, where it is the first time for us to fully design a submarine from the zero point. However, we did not face any major problems getting ideas about the geometry, where various researches and bio-mimicry studies were carried out. After finishing up with the final sketch we faced a major obstacle that impeded our designing process, which was the maneuvering controller system. The submarine had to have a mechanical or electrical controlling system that would provide the users with remote controlling of the submarine for lateral and vertical movement. However, after several researches and ideas from tutors we came up with the flap and rudder control system idea that will be more efficient to drive the vehicle. Subsequently, after closing up with the designing phase and drawing the final 3D sketch on SolidWorks we faced a problem that was immense. The project must be backed up with theoretical or software results to make it officially successful. SolidWorks is a program with a wide range of features that can be used to simulate this project. However, the Flow study of SolidWorks is not available at Bahrain Polytechnic. Therefore, we were advised to use new software which is less complicated than SolidWorks Flow study, this program is ANSYS 14.0. This program is also unavailable at the university, but we managed to get a copy installed in our laptops. The problem did not stop at this point, where we were not able to use the program because we do not have any background about how to use it. After watching videos on YouTube and searching the internet we managed to get a push and get slight knowledge about how to start the program. Though it was hard to use the program, but trial and error was the only way to self-learn how to use it. Dr. Christina was very helpful in giving us more information about the program and the simulation options, where we managed to start getting results from the simulation. After the first simulation, we determined couple of problems regarding the setup options and some geometry defects that disturbs the flow. Nevertheless, these problems were solved and the results were a satisfactory. Time was a critical issue in this project, where more time was needed to get more efficient work done. The program knowledge period wasted a lot of time that could have been used more in improving the current design. Furthermore, it would have been a plus point if we had a water tunnel at the university to test the submarine and get experimental results which are a very reliable back up. This project widened our knowledge sight and increased our experience in designing, researching, 3D sketching, modeling and fluid simulating. The knowledge gained by using the ANSYS 14.0 is a great experience that could open up many doors for further studies. This project did not require any hands-on work, but the benefits were theoretical and program knowledge. Research, Bio-mimicry, 3D modeling, Material selection, Fluid Simulation and Brain storming, all these were the main factors that took this project to higher level and resulted in a successful outcome, educationally and practically.
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Finally, the work placement was a great chance to get more experience in the oil spill field, the trip to the OSR base in Southampton provided us with a great amount of information about how the organization works. Within the trip to OSR base we also visited VIKOMA which is the company that supplies OSR with oil recovery and containing equipment. The whole trip was a great opportunity to visit OSR and VIKOMA, where they are globally known for their reputation. Visiting VIKOMA which is a production company and getting information about how they produce all their products was beneficiary.
Conclusion and recommendations
In this report, we talked and explained all the requirements needed to achieve our final product which is the surveillance submarine. We start by sketching and designing the final model for our project, and then we used the SolidWorks software to draw the 3D model with the correct dimensions to have it ready for simulation. Furthermore, by using the CFD software which is used to made the fluid simulation and determines if the model was successfully sufficient or not. In conclusion, the aim of the project was achieved and all the results were satisfying because of the hard work and continuous support and feedback that we got from Dr. Khalid and Dr. Christina. However, to get a better result for the future I recommend that the university must have some new courses for our mechanical major. For example, adding a course in CFD software which helps to learn how to deal with fluid simulation problems and a course in aero and hydrodynamics. Moreover, the most important thing is to have a water tunnel to have experiments on how the water flow on any object and study the geometry of it.
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Appendix
Figure 84:The picture shows the length of the submarine
Figure 83: The Inlet diameter of the Submarine
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Figure 85 : The picture shows the outer diameter of the submarine
Figure 86: The picture shows the length of the fin which is equal in both sides (right and left)
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Figure 87: The picture shows the length of the dorsal fin
Figure 88: The picture shows the height of the dorsal fin
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Figure 89 : The picture shows the total length from one side wing of the submarine to the other side
Figure 90: The picture shows the length of the side fin (wing)
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Figure 91 : The picture shows the width of the back fin
Figure 92: The picture shows the length of the back fin
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Figure 93: The picture shows the length of the place where the flash light and the camera will fixed
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