AA V7 I3 ANSYS Advantage Turbomachinery

8/12/2019 AA V7 I3 ANSYS Advantage Turbomachinery

1/60

Excellence in Engineering Simulation VOLUME VII| ISSUE 3 | 2013ADVANTAGEADVANTAGE

Spotlight onTurbomachinery

12

Force of Nature16

Pushing the Envelope

26Heart to Heart
http://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machineryhttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machineryhttp://www.ansys.com/


2/60

Realize Your Product Promise ANSYS is dedicated exclusively to developing engineeringsimulation software that fosters rapid and innovativeproduct design. ANSYS technology enables you to predictwith con dence that your product will thrive in the realworld. For more than 40 years, customers in the mostdemanding markets have trusted our solutions to helpensure the integrity of their products and drive businesssuccess through innovation.

ANSYS, Inc.Southpointe275 Technology DriveCanonsburg, PA 15317U.S.A.

For ANSYS, Inc. sales information,call 1.866.267.9724.Email the editorial sta at [email protected] address changes, [email protected].

Neither ANSYS, Inc., nor Wall-to-Wall Studios, Inc., guarantees or warrants accuracy orcompleteness of the material contained in this publication.ANSYS, ALinks, Ansoft Designer, Aqwa, Asas, Autodyn, BladeModeler, CFD, CFX, Chip PowerModule (CPM), Chip Thermal Model (CTM), DesignerRF, DesignerSI, DesignModeler,DesignSpace, DesignXplorer, Engineering Knowledge Manager (EKM), Explicit STR, Fatigue,Fluent, Full-Wave SPICE, HFSS, ICEM CFD, Icepak, Icepro, Maxwell, Mechanical, Mesh Morpher,Multiphysics, Nexxim, Optimetrics, ParICs, PathFinder, PExprt, Poly ow, PowerArtist,PowerArtist Calibrator and Estimator (PACE), Professional, Q3D Extractor, QuickEye, RealizeYour Product Promise, RedHawk, Rigid Dynamics, RMxprt, RTL Power Model (RPM), SCADEDisplay, SCADE Lifecycle, SCADE Suite, SCADE System, Sentinel, SIwave, Simplorer,Simulation-Driven Product Development, Solver on Demand, Structural, Super-Compact, TGrid,Totem, TPA, TurboGrid, Vista TF, VerifEye, WinIQSIM, Workbench, and any and all ANSYS, Inc.brand, product, service, and feature names, logos and slogans are registered trademarks ortrademarks of ANSYS, Inc., or its subsidiaries located in the United States or other countries.ICEM CFD is a trademark licensed by ANSYS, Inc. LS-DYNA is a registered trademark ofLivermore Software Technology Corporation. nCode DesignLife is a trademark of HBM nCode.All other brand, product, service, and feature names or trademarks are the property of theirrespective owners.

Executive EditorFran Hensler

Managing Editor Chris Reeves

Editors Erik FergusonKara GremillionMark RavenstahlJudy Cooper

Editorial Advisor Tom Smithyman

Editorial Contributor ANSYS North AmericaSupport and Services

Art Directors Ron SantilloDan Hart

Graphics ContributorRobin Steed

Design Wall-to-Wall Studios, Inc.

Ad Sales Manager Helen Renshaw

W elcome to ANSYS Advantage! We hope youenjoy this issue containing articles byANSYS customers, sta and partners.Want to be part of a future issue? Theeditorial team is interested in your ideasfor an article. Contact us.The Editorial Sta , ANSYS [email protected]

2013 ANSYS, Inc.

F L E X I B L E S O L U T I O N S F O R T H EE N G I N E E R I N G W O R L D

Optimized compute platformsfor CAE workloadsRemote graphics and batchscheduling enabled

Maximize efciency of available licenses

Simplied integration withinexisting infrastructures

Built with the latestIntel Xeon Processors

sgi.com/solutions
https://storage.ansys.com/video/testimonials/ansys-everywhere.mp4?thelead=truehttps://storage.ansys.com/video/testimonials/ansys-everywhere.mp4?thelead=truemailto:[email protected]:[email protected]:[email protected]://www.sgi.com/solutions/https://storage.ansys.com/video/testimonials/ansys-everywhere.mp4?thelead=truehttp://www.sgi.com/solutions/mailto:[email protected]:[email protected]:[email protected]


3/60


4/60 2013 ANSYS, INC. ANSYS ADVANTAGEVolume VII | Issue 3 | 2013 2

6 12 26

FEATURES

TABLE OF CONTENTS

SIMULATION@WORK

6BEST PRACTICES

Gearing Up for the FutureIncreasing demands for e ciency areonly the beginning; turbomachineryengineers are working diligentlyto improve every aspect of systemperformance.

12THOUGHT LEADER

Force of NatureAs a leader in the global hydropowerindustry, ANDRITZ HYDRO has built areputation for product quality, designrobustness and innovation. Head ofR&D Engineering Methods Mirjam Sickdiscusses how engineering simulationhas supported the companysgroundbreaking design e orts for thepast 25 years and looks toward thefuture of simulation in her industry.

16CENTRIFUGAL COMPRESSORS

Pushing the EnvelopeCFD simulation contributes to increasingthe operating envelope of a centrifugalcompressor stage.

21BEST PRACTICES

1, 2, 3 TurbochargedE ciencySpecialized advanced simulation toolsoptimize turbochargers for increased

power and fuel e ciency.

26HEALTHCARE

Heart to HeartMultiphysics systems simulation leads tobetter understanding of a smaller arti cialheart design.

32AUTOMOTIVE

On the Fast TrackFerrari pushes the limits of simulationin improving aerodynamic performanceof racing cars.

36AUTOMOTIVE

Window of OpportunityRobust design optimization ensureshigh-quality window mechanismsover a wide range of applications.

39AUTOMOTIVE

Safe Automobile ControlsSubaru uses SCADE software todevelop safe and reliable electronicallycontrolled circuits and systems forhybrid electric vehicles.



32 39 44

DEPARTMENTS

ABOUT THE COVEREngineers o f turbomachinery forautomobiles, power plants andother applications face similarengineering challenges. Everyday, they must balance concernsabout operating e ciency orfuel economy with a range ofother initiatives for cost andperformance improvement.Learn more on page 6.

This additional article is available at

www.ansys.com/magazine .

THOUGHT LEADER

Small Systems, Huge Impactimec is a global hub for advancedmicro and nano-electronicsresearch. The companys director ofheterogeneous integrated micro-systems research explains howsystems-level simulation at a tinyscale can yield enormous bene ts

by moving dramatic innovations tomarket, rapidly and reliably.

44ENERGY

Designing forReal-World RepairsLinear and nonlinear structural analysesimprove pipeline repair using compositesmaterials.

48INDUSTRIAL EQUIPMENT

Cool CustomerDesign optimization demonstrates the abilityto reduce engineering time and increase

fatigue life of refrigerant lines on a newgeneration of scroll chillers.

51CHEMICAL PROCESS

On Cloud NineHPC in the cloud reduces runtime for a complex multiphase CFD model withrealistic particle loading from ve days to two days.

54TECH TIP

Accelerating MechanicalSolutions with GPUsGraphical processing units can beused with ANSYS structural mechanicssoftware to solve large, complexmodels faster.

WEB EXCLUSIVE
http://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machineryhttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issuehttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machineryhttp://www.ansys.com/About+ANSYS/ANSYS+Advantage+Magazine/Current+Issue



NEWS

Simulation in the News

HYPERLOOP WILL WORK, SAYSSOME VERY SMART SOFTWAREBloomberg Businessweek businessweek.com, September 2013

Elon Musk unveiled his hyperloop high-speed transportation concept in August;ANSYS fed the speci cations into a com-puter in September to study the feasibil-ity of the idea. The team, led by SandeepSovani, used a virtual mockup of a podand tube to study the air pressure. Thesimulation showed very uneven stressmarkings alongside the body of thepod. We see a lot of shear stress areas,Sovani said. In something like an air-craft, the patterns would be very uni-form. Bearings on the top of the podwould help the device stay balanced dur-ing slight changes in air pressure. Sovaniplans to keep tweaking the design of theHyperloop pods in ANSYS software andeventually send Musk some suggestions.

Sample results from a CFD simulationillustrate velocity vectors of drilling mud ow atthe surface of a drill bit. Color ranges are red formaximum and blue for minimum.

SPEEDING UP DEFENSE SIMSDefense Newsdefensenews.com, July 2013

As exciting as it can be to simulate explosions, developing code for this purpose is pain-staking. A joint project between ANSYS and the Army Armament Research, Developmentand Engineering Center resulted in an interface that wraps around the complex codesused for government simulations to create an easier-to-use environment. The codesmodel objects that explode or the things they hit. Research can be directed at changingbody armor, weapons and the tactics that are used in war. The software should simplifyand speed up research and development by increasing productivity.

SIMULATION AND SENSORS ADVANCE THE DIGITAL OILFIELDOfshoreo shore-mag.com, May 2013

While trying to increase production from oil elds and deepwater reservoirs, R&Dteams face high temperatures and pressures, longer tiebacks and more expensive oper-ations. Author Ahmad Haidari of ANSYS states that companies are developing digitaloil elds with simulation to reduce risk, increase e ciency and maximize recovery.Drilling can be completed more e ciently with electronic sensors on drill bits, lead -ing to faster drilling rates and reduced damage and drill wear. Engineers employ ANSYSsoftware to create robust drilling techniques as they move from traditional methodsto simulation-based techniques. Haidarialso describes how simulation is appliedto ow assurance and vibration, electro -magnetic analysis, and embedded soft-ware that manages the complex inter-action between software, hardware andhuman/machine interfaces.

BENEATH THE LAYERS: COMPOSITE COMPLEXITYDesktop Engineeringdeskeng.com, August 2013

Composites materials are incorporated into many new products, but they arent alwayseasy to work with. Even as engineering software adds features to simulate the abilitiesof composites, designers still face challenges working with these materials because ofthe slight di erences between similar fabrics. When asked about working with compos -ites, ANSYSs Pierre Thie ry admitted that everyone will use a di erent avor of car -bon or fabric, so they will have to characterize it on their own. Thats one of the chal-lenges with composites. Even with such di culties, engineers continue to improveproduct designs with revolutionary materials.

ANSYS AND GOSNIIAS PARTNERTO INCREASE SAFETY IN RUSSIANAEROSPACE INDUSTRYMCADCafemcadcafe.com, August 2013

The state-run scienti c research insti -tute GosNIIAS, which supports aviationdevelopment in Russia, has partneredwith ANSYS to meet worldwide aerospacestandards. Researchers there use SCADEsolutions from ANSYS in an e ort tostreamline code generation of avionicssystem architecture to rapidly improveaircraft safety.
http://www.businessweek.com/articles/2013-09-18/elon-musks-hyperloop-will-work-says-some-very-smart-softwarehttp://www.businessweek.com/articles/2013-09-18/elon-musks-hyperloop-will-work-says-some-very-smart-softwarehttp://www.businessweek.com/articles/2013-09-18/elon-musks-hyperloop-will-work-says-some-very-smart-softwarehttp://www.defensenews.com/article/20130705/TSJ02/307050014/Speeding-Up-Defense-Sims?odyssey=nav%7cheadhttp://www.defensenews.com/article/20130705/TSJ02/307050014/Speeding-Up-Defense-Sims?odyssey=nav%7cheadhttp://www.offshore-mag.com/articles/print/volume-73/issue-5/drilling-and-completion/simulation-and-sensors-advance-the-digital-oilfield.htmlhttp://www.offshore-mag.com/articles/print/volume-73/issue-5/drilling-and-completion/simulation-and-sensors-advance-the-digital-oilfield.htmlhttp://www.deskeng.com/articles/aabkxk.htmhttp://www.deskeng.com/articles/aabkxk.htmhttp://www10.mcadcafe.com/nbc/articles/1/1214436/ANSYS-GosNIIAS-Partner-Increase-Safety-Russian-Aerospace-Industry?interstitial_displayed=Yeshttp://www10.mcadcafe.com/nbc/articles/1/1214436/ANSYS-GosNIIAS-Partner-Increase-Safety-Russian-Aerospace-Industry?interstitial_displayed=Yeshttp://www10.mcadcafe.com/nbc/articles/1/1214436/ANSYS-GosNIIAS-Partner-Increase-Safety-Russian-Aerospace-Industry?interstitial_displayed=Yeshttp://www.deskeng.com/articles/aabkxk.htmhttp://www.offshore-mag.com/articles/print/volume-73/issue-5/drilling-and-completion/simulation-and-sensors-advance-the-digital-oilfield.htmlhttp://www.defensenews.com/article/20130705/TSJ02/307050014/Speeding-Up-Defense-Sims?odyssey=nav%7cheadhttp://www10.mcadcafe.com/nbc/articles/1/1214436/ANSYS-GosNIIAS-Partner-Increase-Safety-Russian-Aerospace-Industry?interstitial_displayed=Yeshttp://www.businessweek.com/articles/2013-09-18/elon-musks-hyperloop-will-work-says-some-very-smart-software



Ferrari uses ANSYS software to gain anadvantage in GT racing.

Use of engineering simulation helped ETNZ toimprove yacht aerodynamic performance in bothdownwind (top) and upwind (bottom) conditions.

Kawa Engineering employed ANSYSsimulation to help locate a powerhouse close toa waterfall in a spot that would reduce ood risk.IMAGE COURTESY KAWA ENGINEERING LTD.

As productsbecome morecomplex, CFDsimulationis helping

to fine-tuneperformanceof existingtechnologies.

SWISS ARMY CFDR&D Magazinerdmag.com, June 2013

CFD initially was a specialized tool usedat aerospace corporations, but it is now

indispensable for product designers inall industries. Applications range fromthe worlds largest hydropower plantto a rear-view car mirror. As productsbecome more complex, CFD is helping to

ne-tune performance. In the academicworld, researchers have approached CFDsimulation as an opportunity to test thelimits of what uid ow analysis can doto further expand the fundamentals ofphysical understanding.

ANSYS, FERRARI EXTENDPARTNERSHIPTenLinkstenlinks.com, September 2013

A world leader in the automotive industry,

Ferrari is improving the endurance of its GTrace cars with ANSYS simulation. Using CFDto optimize critical components, like brakecooling systems and full-body aerodynam-ics, Ferrari improves race cars while work-ing under tight development timelines andstrict regulations. Extending its Formula 1racing relationship with ANSYS to includethe GT division allows Ferrari to validateand quickly optimize designs without los-ing valuable aerodynamic advantages oroverheating brake systems in tough endur-ance races. Learn more on page 32.

SIMULATION SHINES LIGHT ONSOLAR ENERGY

Scienti c Computing World scienti c-computing.com, July 2013

As renewable energy sources becomemore productive and reliable, manufac-turers can bene t greatly from simulationtechnology. Solar energy and solar pan-els are being incorporated into commer-cial building designs; they also are beingadded onto existing homes by ownerswho are interested in producing renew-able energy. ANSYSs Ahmad Haidaristated that the aim is to change the man-ufacturing process so that less materialis used, creating a less expensive prod-uct. More conventional structural engi-neering can be enhanced by simulationto optimize products for stresses andloads, ideal placement, wind-loading andmobility.

ANSYS SPEEDS INTERNATIONAL YACHT RACE WINNERMarineLink marinelink.com, August 2013

Emirates Team New Zealands ability to

deliver fast design improvements to itsyacht with ANSYS CFD helped the teamclaim the Louis Vuitton Cup and a chanceto compete in the 34th Americas Cup. Inthe hypercompetitive sport of yacht rac-ing, Emirates Team New Zealand encoun-tered complex challenges. Simulationdeveloped optimized solutions for theaerodynamic performance of the wingand sails without spending time buildingphysical prototypes.
http://www.ansys.com/staticassets/ANSYS/staticassets/resourcelibrary/casestudy/KAWA-Case-Study.pdfhttp://www.ansys.com/staticassets/ANSYS/staticassets/resourcelibrary/casestudy/KAWA-Case-Study.pdfhttp://www.ansys.com/staticassets/ANSYS/staticassets/resourcelibrary/casestudy/KAWA-Case-Study.pdfhttp://www.ansys.com/staticassets/ANSYS/staticassets/resourcelibrary/casestudy/KAWA-Case-Study.pdfhttp://www.ansys.com/staticassets/ANSYS/staticassets/resourcelibrary/casestudy/KAWA-Case-Study.pdfhttp://www.rdmag.com/articles/2013/06/swiss-army-cfdhttp://www.rdmag.com/articles/2013/06/swiss-army-cfdhttp://www.tenlinks.com/news/PR/ansys/092013_ferrari.htmhttp://www.tenlinks.com/news/PR/ansys/092013_ferrari.htmhttp://www.scientific-computing.com/http://www.scientific-computing.com/http://www.marinelink.com/news/international-speeds358015.aspxhttp://www.marinelink.com/news/international-speeds358015.aspxhttp://www.scientific-computing.com/http://www.marinelink.com/news/international-speeds358015.aspxhttp://www.tenlinks.com/news/PR/ansys/092013_ferrari.htmhttp://www.ansys.com/staticassets/ANSYS/staticassets/resourcelibrary/casestudy/KAWA-Case-Study.pdfhttp://www.rdmag.com/articles/2013/06/swiss-army-cfd



BEST PRACTICES

T he turbo sector faces the pressingchallenge of increasing th e energye ciency of not only the worldsmore than 3 million major turboma-chines but all turbo-related equipment,whether it burns fuel directly (as in thecase of gas turbines) , whether energy isconsumed in the process of driving themachines (as with industrial compressors) ,or whether it extracts energy from a owstream (as for water turbines ). Its beenproven that even fractional improvementsin fuel performance yield substantial eco-nomic bene ts. Experts estimate that justa 1 percent increase in fuel efficiencywould deliver $30 billion in savings forthe global commercial aviation industryover a 15-year horizon. The worlds gas-powered energy plants could realize a$66 billion nancial bene t by achievingthat same 1 percent improvement [1].

GearingUp for the

FutureIncreasing demands for efficiency are onlythe beginning; turbomachinery engineers areworking diligently to improve every aspectof system performance.

While e ciency is a huge concern, itis only one urgent priority on the agendaof the worlds turbomachinery engineers.

Every day, they must balance concernsabout operating efficiency or fuel econ-omy with a range of other initiatives forcost and performance improvement.Energy e ciency initiatives are not onlydriven by cost, but also by environmentalconcerns, since reduced energy consump-tion generally relates to reduced carbonemissions (and it is one concrete way ofmeasuring progress and compliance).

For example, according to theInternational Air Transport Association,in 2012 fuel costs accounted for approxi-mately 33 percent of the overall expensesof the worlds airlines [2] but the other67 percent of costs relates to applicationsthat could benefit from improvementas well. To succeed in an increasingly

crowded global marketplace, airlines aredriving costs out of every area of theiroperations, including aircraft mainte-

nance. Every innovation that targets fuelefficiency such as new compositesmaterials that reduce weight must meeta host of other performance criteria. Theymust be proven durable enough to alsoreduce lifetime maintenance and repaircosts. And, of course, composites mustdemonstrate su cient strength to ensurepassenger safety under a full range of

ight conditions.Engineers of turbomachinery for auto-

mobiles, power plants and other applica-tions face similar Catch-22 engineeringchallenges. While the universal mandatefor increased e ciency receives an enor -mous amount of attention as well asa large percentage of R&D dollars thereality is that it is just one performance

By Brad Hutchinson, Vice President of Industry Marketing, Turbomachinery, ANSYS, Inc.
http://www.ansys.com/Business+Initiatives/Improving+Energy+Efficiencyhttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machineryhttp://www.ansys.com/Business+Initiatives/Improving+Energy+Efficiencyhttp://www.ansys.com/Business+Initiatives/Improving+Energy+Efficiencyhttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Gas+&+Steam+Turbineshttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Pumps+&+Water+Turbineshttp://www.ansys.com/Business+Initiatives/Improving+Energy+Efficiencyhttp://www.ansys.com/Business+Initiatives/Improving+Energy+Efficiencyhttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machineryhttp://www.ansys.com/Business+Initiatives/Improving+Energy+Efficiencyhttp://www.ansys.com/Business+Initiatives/Improving+Energy+Efficiencyhttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Pumps+&+Water+Turbineshttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Gas+&+Steam+Turbines



Specialized transient blade row methodscan accurately predict blade rowperformance over time and a range ofreal-world operating conditions.

consideration. Optimizing reliability,safety, operating exibility, noise, main -tenance, environmental impact and time

to market are other design pressures thatturbo engineers feel acutely.

Because of ongoing demands toimprove performance, turbomachin-ery engineers were among the first toembrace the power of engineering simu-lation. From the earliest days of simula-tion use in the sector, product developersrecognized the power of building, testingand verifying their advanced systems ina cost-e ective, low-risk virtual world. Byidentifying performance issues at an earlystage, before making large investments oftime and money in prototypes, turboma-chinery engineers have made incrediblestrides in continually improving overalldesign robustness, along with introduc-ing innovative performance features.

BLADE ROWS:NEW TRANSIENT TECHNIQUESThe uid ow through blade rows a ectsmany aspects of turbomachine perfor-mance, including work input or output,e ciency and operating range. For prac -tical reasons, traditional analysis of bladerows has focused on steady-state perfor-mance. As good as it is, steady-state anal-ysis fails to capture all the real-worldintricacies of the ow as one row of bladesrotates past another.

Specialized transient blade row meth-ods from ANSYS called transformationmethods accurately predict blade rowperformance over time, as well as over arange of real-world operating conditions.Irrespective of pitch ratio, these methodsrequire modeling only one or two bladesper row yet still yield a full-wheel tran-sient solution. Not only are problem-solv-ing time and data storage space reduceddramatically, but smaller output filesmean much faster post-processing of sim-ulation results.

ANSYS has partnered with Siemensand other turbomachinery customers toapply these new transformation methods

to a range of product design challenges.The results include dramatic improve-ments in simulation time and cost, cre-ating a signi cant competitive advantage

while also ensuring that product integ-rity is maintained.

New features and capabilities in ANSYSsoftware enable engineers to predictturbomachinery performance and solveproduct design challenges faster thanever, with a high degree of con dence.

Today, as product development teamsin this segment face more-intense pres-sures than ever before, engineering sim-ulation has risen to the top of the list asa critical competency. Computer-aideddesign tools help to elucidate perfor-mance trade-o s at an incredible level ofdetail. Engineers can readily learn howtheir speci c energy-e ciency initiatives,such as increased combustion tempera-tures, a ect related performance featureslike materials strength and durability. Byproviding insight into these trade-offs,engineering simulation has supported thedevelopment of many important technol-ogy advancements in turbomachinery.

Today, new features in ANSYSsoftware combined with robustdesign practices and powerful high-performance computing environments

enable engineers to predict turboma-chinery performance and solve prod-uct design challenges faster than ever,with a high degree of con dence. Eventhe most complex design problemscan be illuminated and addressed atan exacting level, as engineers striveto make ongoing improvements that

balance efficiency gains with othercritical design criteria. Following is a dis-cussion of some of todays most advancedturbomachinery design challenges aswell as strategies for answering them viaengineering simulation.
http://www.ansys-blog.com/2012/02/15/transient-blade-row-methods-obtaining-accurate-transient-turbomachinery-solutions-faster-3/http://www.ansys-blog.com/2012/02/15/transient-blade-row-methods-obtaining-accurate-transient-turbomachinery-solutions-faster-3/http://www.ansys-blog.com/2012/02/15/transient-blade-row-methods-obtaining-accurate-transient-turbomachinery-solutions-faster-3/



BEST PRACTICES

ANSYS has developed new high- delitysimulation techniques for aeromechanicsstudies. By coupling ANSYS Mechanicalwith ANSYS CFX transformation meth-ods for transient blade row analysis,product development teams can simulta-neously consider the aerodynamics and

mechanics of the blade row. Softwarefrom ANSYS supports the close couplingof multiple physics required to study thenuanced interactions of the uid ow andbladed components.

AEROMECHANICS: MINIMIZINGVIBRATION AND FLUTTERA catastrophic failure at the SherburneCounty Generation Station in Minnesotain late 2011 caught the attention of theglobal turbomachinery industry. Duringan overspeed testing exercise, vibration

was observed, then the blades broke; the80-ton rotor was twisted, and metal com-ponents were thrown into an adjacentcontrol room. While no one was harmed,this turbine failure is costing utilityXcel Energy more than $200 millionand months of equipment downtime [3].In public statements, Xcel noted that thevibration problem was a function of theoriginal product design [4] bringingnew attention to the critical need to iden-tify failure modes at the earliest possibledesign phase.

To help turbomachinery engineersmeet vibration and flutter challenges,

Software from ANSYS supports theclose coupling of multiple physicsrequired to study the nuancedinteractions of uid ows andbladed components.

Siemens and ANSYS are collaborating on the application of steady and transient blade row methodsto the Siemens Platform Compressor test rig, a half-scale multistage industrial axial compressor.One objective is improved prediction of compressor stall. Good comparison between experiment andsimulation has been observed, as reported in recent ASME Turbo Expo papers. COURTESY SIEMENS.

Blade utter can be accurately mod -eled via unsteady simulations for anyrange of nodal diameters using Fouriertransformation methods. Forced responsemethods enable an assessment of stabil-ity that considers unsteady flows, pre-dicted by modeling only one or two blades

per row. High-speed, iterative solvers fromANSYS reduce processing time, while stillensuring the high fidelity and designrobustness needed to deliver safe, reliableresults in real-world product applications.
http://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics/ANSYS+Mechanicalhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Fluid+Dynamics+Products/ANSYS+CFXhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Fluid+Dynamics+Products/ANSYS+CFXhttp://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics/ANSYS+Mechanical



COMPOSITES: ENSURING HIGHSTRENGTH, RELIABILITYWhile composites materials have gar-nered much attention for their inclu-sion in car bodies and aircraft fuselages,they also have important applications in

turbomachinery. By fabricating turbineblades from these advanced materials,wind power companies in particular havecombined light weight with outstandingaerodynamic performance.

ANSYS o ers a specialized tool, ANSYSComposite PrepPost, for modeling layeredcomposites while ANSYS MechanicalAPDL supports simulations of ceramicmatrix composites. These materialsshow special promise because they canwithstand the high temperatures associ-ated with many turbomachinery applica-tions. Earlier this year, ANSYS expandedits focus on composites modeling withits acquisition of EVEN EvolutionaryEngineering AG a leading global pro-vider of composites analysis and optimi-zation technology.

This growing portfolio of compositesmodeling solutions allows turbomachin-ery engineers to de ne the optimal mate -rials formula and layering strategy, thensubject their designs to simple physi-cal stresses. By computing progressive

damage, delamination and cracking,engineers can confidently predict fail-ure modes under demanding conditions.As the role of composites grows in theworldwide turbomachinery industry, thecapabilities of ANSYS software will alsoexpand to anticipate evolving user needs.

COMBUSTION MODELING: NEWACCURACY AND FIDELITYThe global drive for greater energy e -ciency has placed a new focus on the com-bustion processes that lie at the heart ofmany turbomachines. Higher ring tem -peratures can improve e ciency, yet theycan degrade engine materials and shortenproduct life unless appropriate measuresare taken.

As turbomachinery engineers explorecombustion innovations, they can relyon ANSYS for new capabilities that modelthe complexities of combustion moreaccurately than ever. Advanced model-ing techniques from ANSYS includ-ing thickened flame, improved sprayand fuel evaporation models allow

Composites modeling solutions allowturbomachinery engineers to de ne theoptimal materials formula and layeringstrategy, then subject their designs tosimple physical stresses.

Airlines are driving costs out of every area of their operations.

Scale-resolving simulation (SRS) methods from ANSYS accurately capture large-scale structuresin the combusting ow supporting turbomachinery engineers as they explore new combustionstrategies.
http://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics/ANSYS+Composite+PrepPosthttp://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics/ANSYS+Composite+PrepPosthttp://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics/ANSYS+Composite+PrepPosthttp://www.ansys.com/Industries/Materials+&+Chemical+Processing/Application+Highlights/Combustion+Systemshttp://www.ansys.com/Industries/Materials+&+Chemical+Processing/Application+Highlights/Combustion+Systemshttp://www.ansys.com/Industries/Materials+&+Chemical+Processing/Application+Highlights/Combustion+Systemshttp://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics/ANSYS+Composite+PrepPosthttp://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics/ANSYS+Composite+PrepPost



engineers to better determine fuelairmixing, ame position, temperature dis -tribution and pollutant formation withincombustors. High- delity meshing capa -bilities, combined with advanced turbu-lence modeling, give ANSYS users an edge

by resolving the geometry and ow to thedegree required for accurate simulation.

Turbulence can be modeled via a vari-ety of methods, depending on the needsof the engineering team and the speci ccombustion issue under study. ANSYSoffers scale-resolving simulation (SRS)methods such as large- and detached-eddy simulation (LES and DES) as wellas efficient scale-adaptive simulation(SAS) tools.

ROTORDYNAMICS:ENSURING STABILITYTo combine light weight and a small pro-file with incredibly high strength, tur-bomachinery engineers make strategictrade-o s as they design rotor systems.Not only do they need to understandthe dynamics of each individual com-ponent, but they need to optimize thefrequencies and vibration modes of thesystem as a whole.

The compatibility of ANSYSsolutions with high-performancecomputing environments combined with the rapid solversin ANSYS software has takenheat transfer modeling to a newlevel of speed and exibility.

ANSYS software helps to illuminatethese trade-offs by demonstrating howspeci c design choices such as shaftsize, bearing properties and spacing, andhousing stiffness will impact suchperformance characteristics as operatingrange and stability.

ANSYS has been steadily increas-ing its capabilities to support engi-neering teams in designing rotatingmachinery. Specialized functions in

ANSYS Mechanical APDL help to stream-line the import process for bearing prop-erties, as well as for other componentproperties. Multi-spool simulation capa-bilities enable realistic simulation ofmodern aircraft engines. Engineers havethe exibility to create full 3-D models ofrotor systems or reduce their designs toaxisymmetric models for faster analysis.

HEAT TRANSFER: OPTIMIZINGTHERMAL PERFORMANCEAs pressures escalate to increase energye ciency via higher temperatures, ther -mal management issues are coming to theforefront among turbomachinery teamsaround the world.

By coupling ANSYS MechanicalwithANSYS CFDproducts, engineers ensurethat engine materials can withstandhigh temperatures while also optimiz-ing the e ectiveness of their engine cool -ing strategies. Running these types of

multiphysics studies is easier than everdue to improved capabilities in ANSYSWorkbench to link uid ows, conjugateheat transfer, thermal and mechanicalstress, and deformation. Advanced turbu-lence models from ANSYS also support thestudy of complex heat transfer processes.

With the need to simulate multiplephysics under a comprehensive rangeof real-world operating conditions, heattransfer simulations can be very large andnumerous. The compatibility of ANSYSsolutions with high-performance com-puting (HPC) environments combinedwith the rapid solvers in ANSYS software has taken heat transfer modeling to a newlevel of speed and exibility.

BEST PRACTICES

New transient blade row analysis capabilities in ANSYS CFX can be coupled with ANSYSMechanical to simulate only one or two blades per row in an unsteady state. Blade vibration andfailure modes can be identi ed across the full wheel, at a fraction of the previous computationaltime, cost and computing resources.
http://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flowshttp://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flowshttp://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flowshttp://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flowshttp://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flowshttp://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flowshttp://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flowshttp://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flowshttp://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flowshttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamicshttp://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics/ANSYS+Mechanicalhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamicshttp://www.ansys.com/Products/Workflow+Technology/ANSYS+Workbench+Platformhttp://www.ansys.com/Products/Workflow+Technology/High-Performance+Computinghttp://www.ansys.com/Products/Workflow+Technology/High-Performance+Computinghttp://www.ansys.com/Products/Workflow+Technology/High-Performance+Computinghttp://www.ansys.com/Products/Workflow+Technology/High-Performance+Computinghttp://www.ansys.com/Products/Workflow+Technology/ANSYS+Workbench+Platformhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamicshttp://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics/ANSYS+Mechanicalhttp://www.ansys.com/Resource+Library/Technical+Briefs/Turbulence+Modeling+for+Engineering+Flows



ANSYS: CONTINUING TO RAISETHE BARIn this issue of ANSYS Advantage, youll

nd many examples of how ANSYS cus-tomers apply advanced technologies toemerge as global leaders in turboma-chine e ciency as well as other criticalaspects of equipment performance.

Dresser-Rand employs engineer-ing simulation to achieve a wider oper-ating range for centrifugal compressorsso these machines can operate reli-

ably under the broad range of ow ratesrequired by processing industries. MirjamSick, head of R&D engineering meth -ods at ANDRITZ HYDRO, explains howher company has used ANSYS technol-ogy for about 25 years to arrive at innova-tive new designs that deliver dependable,robust performance for clients around theworld. Turbomachinery experts from PCAEngineers describe how they optimize tur-bochargers for increased performanceand e ciency.

Whatever your own turbomachin-ery engineering challenges, youll prob-ably be inspired by these real-worldtestimonies to the power of engineeringsimulation.

Turbomachines may never be simple tooptimize. But ANSYS will continue to makeadvancements in our ability to model andpredict turbomachinery performance.

ANSYS partnered with PCA Engineers to model total blade surface displacement forNASA Rotor 67. To identify potential failure modes, the ANSYS-PCA team used unsteadycalculations that relied on Fourier transformation methods.

Every day, engineers must balance concernsabout operating e ciency or fuel economywith a range of other cost- and performance-improvement initiatives.

While few applications are as com-plex as turbomachinery, the good news

is that turbomachinery engineers havealways been among the rst to embraceimproved simulation capabilities to meettheir advanced challenges.

Turbomachines may never be simpleto optimize. But for more than 40 years,ANSYS has partnered with customersworldwide to make continuing advance-ments in the ability to model and predictturbomachinery performance. Today weare all focusing on improving e ciency,but who knows what the future maybring? Whatever challenges lie ahead,ANSYS is committed to meeting theneeds of this complex and ever-changingindustry.

References[1] Evans, P. C.; Annunziata, M. Industrial Internet:

Pushing the Boundaries of Minds and Machines , GE,November 26, 2012.

[2] Fact Sheet: Fuel. http://www.iata.org/

pressroom/facts_ gures/fact_sheets/pages/fuel.

aspx.

[3] Sha ner, D. "Sherco Power Plant Repairs May

Take 16 Months, Cost $200 Million". Star Tribune,

October 2, 2012, http://www.startribune.com/

business/172394411.html.

[4] Sha ner, D. "Failed Turbine Blades CausedXcel Energys Generator Accident". Star Tribune ,

April 15, 2013, http://www.startribune.com/

business/203120471.html.



H eadquartered in Vienna, Austria, ANDRITZ HYDRO is aglobal supplier of electromechanical systems and ser-vices for hydropower plants. As one of the leaders in theworld market for hydraulic power generation, the company hasinstalled more than 30,000 turbines globally, which are capableof producing 400,000 megawatts of output.

To keep pace with changes in international energy needs,growing environmental concerns and tightening governmentregulation, ANDRITZ HYDRO relies on engineering simulationto arrive at innovative new turbomachinery designs that deliverreliable, robust performance for customers around the world.

This longtime ANSYS customer leverages the power of simula-tion to help customers retro t aging hydropower plants with newtechnologies as well as to troubleshoot performance issues forexisting power generation systems.

As head of R&D Engineering Methods, Mirjam Sick man-ages the organizations engineering simulation e orts and othercritical design activities. Recently, ANSYS Advantage askedSick about the competitive challenges that ANDRITZ HYDROfaces today, how her team uses engineering simulation tomeet these challenges, and her perspective on the future ofhydropower engineering.

THOUGHT LEADER

FORCE OFNATURE

P H

O T

O C

O U R T E

S Y

A N D R I T Z H Y D R

O

As a leader in the global hydropower industry, ANDRITZ HYDRO has built a reputationfor product quality, design robustness and innovation. Head of R&D EngineeringMethods Mirjam Sick discusses how engineering simulation has supported thecompanys groundbreaking design efforts for the past 25 years and looks towardthe future of simulation in her industry.

By ANSYS Advantage Sta



What are the biggest challenges facing the hydropower

industry today and what role do engineers play in overcom-ing them?The global hydropower industry has changed dramatically in thepast decade, re ecting changes in the broader energy industry.As other renewable energy sources, such as solar and wind, havegrown in capabilities, the energy grid looks very di erent today.This has resulted in enormous demand swings for hydropowerplants. At one time, demand was stable and plants were runningcontinuously but today there is a great deal of variability. Thismeans that hydropower turbines, pumps and hydraulics mustbe designed for exible operation and performance that is farmore dynamic in nature. Our engineering teams must now ana-lyze how equipment performs under o -design conditions thatwe would not have considered 10 years ago including dynamicloads and ows that are close to stability limits. We must buildour machinery to change quickly and e ciently to new operat -ing modes. Its not enough to design for the best-possible condi-tion; our engineers must analyze performance over time, under

conditions that are constantly changing. We need to considerhow varying loads and ows a ect lifetime performance. Weneed to design turbines that are incredibly robust and reliable.ANDRITZ HYDRO has an outstanding reputation for product qual-ity, and we are working hard today to uphold that tradition, evenas our engineering challenges have grown in complexity.

How has your use of engineering simulation evolved to helpyou meet these new performance demands?Our engineers are doing more time-dependent simulationsinstead of focusing only on steady-state equipment performance.Were looking at the interactions of static and rotating parts,instead of focusing only on the parts that are moving. Were per-forming dynamic stress analysis that allows us to increase ourunderstanding of the impacts of changing ows and loads. Time-dependent methods are required to analyze starts and stops ofgenerators and turbines. In addition, our engineering team isconducting one-way coupling for computational uid dynamics(CFD) and nite element method (FEM) studies. Electromagnetics(EM) simulation tools are helping us to optimize the performanceof generators over their lifetimes.

Fortunately, as our engineering needs have become moreadvanced, engineering simulation tools have grown in theirsophistication and their ability to support these kinds of in-depth, multiphysics analyses. Weve been very pleased withthe way ANSYS software has improved over time to add thesecritical capabilities. Designing our advanced turbines, pumpsand hydraulics without simulation tools would not be possible.Fortunately, ANSYS not only provides these simulation tools, butdelivers excellent support for our analyses. The software enablesus to replicate an incredible level of product complexity, as wellas very challenging operating conditions, in a low-risk virtualdesign environment.

How does ANSYS software help create a competitive advan-tage for ANDRITZ HYDRO?Our company is known in the industry for our engineeringknowledge and our expertise in R&D. Worldwide customers cometo us for superior new designs as well as for ideas to improve the

Our engineers must analyze performance over time,under conditions that are constantly changing.

Software from ANSYSenables us to replicate

an incredible level ofproduct complexity.
http://storage.ansys.com/video/testimonials/andritz-hydro.mp4



performance of their existing hydropowersystems. We rely on ANSYS software toshow customers that expertise in a visualway. If we are developing a new turbinesystem or refurbishing an older plant, weoften show customers ANSYS simulationgraphics that demonstrate exactly howthe new machinery will work or exactlywhere current performance problemsarise, in the case of a plant retro t. Our

ANSYS tools help us interact with custom-ers in a very professional and serious way,demonstrating our engineering knowl-edge in a straightforward manner. Thefact that we have validated all our designsvia ANSYS gives our customers great con-

dence in ANDRITZ HYDRO. They trustthat our systems will work as promised.

We need to model complex

problems much faster to arrive atnew, exible hydropower systems.

THOUGHT LEADER

ANDRITZ HYDRO is a good exampleof a global business, with a global engi-neering team. How do you facilitate col-laboration among your engineers?In my view, its critical to have all ourengineers using the same set of tools,including ANSYS software. This allowsus to standardize our processes and ourproblem-solving approach across theentire organization no matter what

specific customer challenge our indi-vidual engineers are focused on. Wehave been using ANSYS tools for about25 years, and today we have more engi-neers doing simulation than ever before.That level of product innovation cre-ates obvious strategic benefits, but italso means that we must continually

share knowledge and encouragecollaboration. Our global engineeringteam comes together in phone calls andmeetings on a regular basis. We nd iteven more important that, every day, teammembers are applying the same toolkit

and advancing our collective knowledgeof how to best leverage engineering simu-lation as a discipline.

What trends do you see in hydro-power engineering over the next ve to10 years?While other renewable power generationsystems are receiving a lot of attention,hydropower is still the most cost-e cientand readily available source of renewableenergy. Today, only about 20 to 25 percentof global hydropower resources have beendeveloped, which means there is hugegrowth potential in our industry.

One important opportunity is todevelop tidal turbines, or underwaterwindmills, that rotate based on the nat-ural movement of tides. While this is apromising area, it represents an enor-mous engineering challenge. It is di cultto accurately assess the changing envi-ronmental loads of this type of power gen-eration system. Any system would haveto be designed for outstanding strength,since it is subject to rough conditions and,at the same time, di cult to access andmaintain. I think over the next decade weare going to see hydropower engineersmaster this challenge and develop tide-based hydropower plants that help theworld address its energy challenges. Thiswill be exciting to witness.

In more traditional hydropowerinstallations, I think the biggest engineer-

ing challenge will be designing systemsthat can go from zero power to 100 per-cent power very quickly, without any lossin long-term reliability. This means min-imizing cavitation, vibration, and othersources of stress and wear within ourmachines. As consumer needs continue to

uctuate, and the energy grid evolves inits composition, the pressure to operate atvariable speeds will only increase.

Engineering simulation softwaremust expand its capabilities for us tomeet these challenges. Time-dependentstudies, turbulence modeling, ow insta -bility and separation, vortex modeling,heat transfer in generators we needto model these types of complex prob-lems much faster to arrive at new, exible

Pump impellers used for irrigation of agricultural land COURTESY ANDRITZ HYDRO.



Optimizing System Performance

While ANDRITZ HYDRO is known for its innovative hydro-

power products, the company also applies its engineeringknowledge to help troubleshoot problems in systems manu-factured by competitors. Recently, the engineering team atANDRITZ HYDRO was called upon to solve performance prob-lems at a hydropower plant located in New Zealand.

Because we use ANSYS software to simulate systems-levelperformance on a standard basis, we were able to quickly

Without ANSYS, we would bebuilding suboptimal machines.

I love the exible way we are able to useANSYS tools today to conduct root-causeanalysis and add value for our customers.

hydropower systems. Simulation softwarefrom ANSYS has made tremendous stridessince ANDRITZ HYDRO started usingthese tools 25 years ago, and Im con -dent that ANSYS software will continue toevolve to meet our increasingly sophisti-

cated user demands.

How would you describe your rela-tionship with ANSYS?ANDRITZ HYDRO has enjoyed a very closerelationship with ANSYS. In fact, I wouldcall it a development partnership. Wehave obviously bene ted from our abil -ity to apply ANSYS tools to validate ourengineering designs. In turn, we havehelped ANSYS understand the needs ofvery advanced users, and this has helpedthem to improve the modeling capabili-ties of their tools. For new and complexapplications, we have been collaborat-ing by providing test cases, testing alphaversions of models, and working withdedicated research licenses. WithoutANSYS, we would be building suboptimalmachines. By using ANSYS, and partner-ing with them to provide ongoing feed-back, we can o er our customers a veryhigh level of design robustness and prod-uct con dence. I would say we have a verygood partnership with ANSYS that hasbene ted ANSYS, ANDRITZ HYDRO andour global customers.

Simulation of a Francis turbine COURTESY ANDRITZ HYDRO.

model this existing system. We observed some damage and sus-

pected that a mistake in the basic design was causing wear issues.We identi ed the root cause of the problem which was cavi-tation in the systems guidevanes, said Mirjam Sick of ANDRITZHYDRO. We changed the design to minimize the cavitation, andthe problem was solved in a very rapid, straightforward manner.I love the exible way we are able to use ANSYS tools today to con-duct root-cause analysis and add value for our customers.
http://www.ansys.com/Products/Simulation+Technology/Systems+&+Multiphysicshttp://www.ansys.com/Products/Simulation+Technology/Systems+&+Multiphysics



CENTRIFUGAL COMPRESSORS

Dresser-Rand designs compressorstages to operate at higher ow

coe cients and higher machine orinlet-relative Mach numbers.

Pushing theEnvelope

CFD simulation contributes to increasing the operatingenvelope of a centrifugal compressor stage.By James M. Sorokes, Principal Engineer; Jorge E. Pacheco, Manager, Aero/Thermo Design Engineering; andKalyan C. Malnedi, Manager, Solid Mechanics Group, Dresser-Rand Company, Olean, U.S.A.

C entrifugal compressors, alsocalled radial compressors, playa critical role in many processindustries, including oil and gas, petro-chemical, and gas transmission. Thesemachines are used to compress a gas

or a gasliquid mixture into a smallervolume while increasing its pressureand temperature.

COMPRESSOR DESIGNCHALLENGESProcess industries are looking for smaller-footprint compressors for space-sensi-tive applications, such as o shore, subseaand compact plant designs. Dresser-Randreduces compressor footprints by design-ing stages to operate at higher flowcoe cients and higher machine or inlet-relative Mach numbers. The companyis among the largest global suppliers ofrotating equipment solutions for long-life,critical applications.

In recent years, the industry hasplaced greater emphasis on achieving awide operating range so that, for exam-ple, compressors can handle a widerrange of ow rates at di erent stages ofa wells lifecycle. Engineering simulation

is an important tool in addressing thesemarket challenges. Dresser-Rand hasbeen using ANSYS CFX software since the1990s to develop many new compressordesigns for process industries and otherapplications.

Two factors limit the overall operatingrange of a compressor: surge or stall mar-gin, and overload capacity. Surge or stallmargin limits the compressors ability tooperate at ow rates lower than design,while overload capacity limits the ability

to operate at higher rates. Rotating stallarises when small regions of low momen-tum or low pressure (referred to as stallcells) form in the ow passages and beginto rotate around the circumference of thecompressor. These ow and/or pressure
http://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Fluid+Dynamics+Products/ANSYS+CFXhttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Fluid+Dynamics+Products/ANSYS+CFXhttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargers



Centrifugal compressors operate by adding velocity pressure or kinetic energy to the uid stream and then converting that kinetic energy into potentialenergy in the form of static pressure. Kinetic energy is added by rotating impellers, while the conversion of velocity pressure to static pressure occurs indownstream stationary components such as di users, return channels and volutes.

disturbances cause unbalanced forces onthe compressor rotor, leading to unwantedvibration issues and reduced compres-sor performance. Surge occurs when thecompressor is no longer able to overcomethe pressure in the downstream pip-

ing and pressure vessels, and the ow isforced backward through the compressor.

For most centrifugal stages that oper-ate at high inlet-relative Mach numbers,low-momentum regions can form alongthe shroud side of parallel-wall vanelessdi users. Typically the size of this regionincreases as ow is reduced until di userstall results. In developing a new high-head stage for a highMach number com-pressor, the Dresser-Rand team observedan interesting phenomenon both in com-putational uid dynamics (CFD) simula -tion and test results: A sudden migration

of the low-momentum region from theshroud side to the hub side of the di useroccurred as the flow rate reduced, justprior to stall [1]. The impeller used in thestudy is operated over a machine Machnumber range of 0.85 to 1.20. The initial

design had a vaneless di user that waspinched at the shroud and then followedby a parallel wall section. In analyzingtest results, engineers established thatthe shift of the high-momentum regionoccurred much earlier for this high-headstage than for lower-head stages. As aresult, the surge margin was signi cantlylower than low-head stages, an unac-ceptable drop in operating range. Sincethe stationary components were stallingbefore the impeller due to low momentumshift, the team decided to use CFD to opti-mize the di user and return channel.

USING CFD TO OPTIMIZETHE DESIGNDresser-Rand engineers conducted allanalyses using ANSYS CFX software for asector model that included the upstreaminlet guide vane, impeller, di user, return

bend, return channel and exit section. Inthis case, the grid was composed of morethan 5 million total elements using a tet-rahedral mesh with wedge elements forthe boundary layers. Engineers modeledthe interfaces between stationary androtating components using a stage inter-face that performs a circumferential aver-aging of the uxes through bands on theinterface. The k-epsilon turbulence modeland a high-resolution discretizationscheme were used.

The team evaluated several combi-nations of pinch, shroud-tapered and




hub-tapered di users. Engineers iterated to a di user designthat is pinched and tapered on both hub and shroud sides tosigni cantly reduce low-momentum regions that were formingon either side of the di user exit at low ow. They reduced thereturn channel width and redesigned the return channel vanesto match the new ow incidence. CFD results showed that thenew design signi cantly reduced the size of the low-momentumregion in the di user and return channel. It also considerablydelayed the shift of the low-momentum region from the shroudside to the hub side, delaying the onset of stall.

Comparison between the original and optimized designsshows a substantial reduction in the absolute velocity ow angle

Velocity pro le at 90 percent ow for the optimized stationary component design shows a muchsmaller low-momentum region.

Absolute velocity ow angle at the di user exitfor the original design shows high tangential- owangles, indicative of low-momentum ow thatoften leads to formation of stall cells.

Absolute velocity ow angle at the di userexit for the optimized design shows greatlyreduced high tangential- ow angles.

Inlet

Inlet guide vane

Impeller

Hub

Velocity pro le at 90 percent ow for the original stationary component design shows a largelow-momentum region at the hub side in the vaneless di user and return bend.

relative to the radial line at the di user exit plane. Highly tan -gential ow angles greater than 75 degrees generally are indic -ative of very low momentum, which leads to formation of stallcells in stationary components. The pressure recovery plots forboth original and optimized geometries show that the optimizedgeometry has lower pressure recovery on the overload side butbetter performance on the surge side. The lower recovery at over-load for the optimized geometry is most likely due to the nar-row stationary component passages, which results in higher gasvelocities and lower pressure recovery. However, this geometryalso contributes to improving the ow in the stationary compo -nents, resulting in better pressure recovery at lower ow. The

Return bend

Vaneless di user

ShroudReturn channel vanes
http://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargers



Structural AnalysisDresser-Rand structural engineers optimize the impellerdesign to keep the static stresses both below those seen insimilar families of impellers and below allowable mate-rial yield strengths. The lower the stresses, the faster theimpeller can be run. During the design process, engineersalso analyze the design to see if there are any possible res-onance issues caused by upstream or downstream station-ary components.

Most of the time, structural damages to the impellersare due to mechanical fatigue. Dresser-Rand follows the in-house dynamic audit process [3] to evaluate the fatigue lifeof the impellers. The dynamic audit process involves a seriesof successive analysis runs, starting with a modal analysis

and plotting of a SAFE diagram [4] for identifying interfer-ences. This is followed by harmonic response analyses tocompute dynamic stress levels in an impeller at identi edSAFE interferences. A minimum factor of safety is then com-puted for all locations in the impeller based on the static anddynamic stresses, material properties and the constructionmethod used for that impeller. The structural team has auto-mated much of the structural design process by writing APDLmacros and FORTRAN programs, which have reduced sim-ulation time from more than a week to one to two days perdesign iteration.

Typical steady-state plot of impeller

Industrial centrifugal compressor COURTESY DRESSER-RAND.

Tests validated CFD simulation prediction of

about 10 percent improvement in the surgemargin of the new design.

CFD results predicted an improvement in surge margin of approx-imately 15 percent.

Tests validated CFD simulation prediction of an improve-ment of about 10 percent in the surge margin of the new design.Flow angle measurements at the di user inlet, di user exit andreturn channel inlet con rmed the CFD prediction of a delay inthe low-momentum shift. Further, the redesign was successfulin maintaining the same head and e ciency levels as the pre -vious design had. About 1.5 percent of overload margin waslost due to the reduced passage areas in the stationary compo-nents. However, this was deemed acceptable, as the stage is notexpected to be operated at high ow levels close to choke.

Impellers are subjected to inlet and exit flow variationsthrough the stage, and therefore they must be designed to with-stand the alternating pressure loads due to these variations inaddition to withstanding steady loads. The structural team usedANSYS Mechanical software and in-house tools to ensure that thenew design meets the static and dynamic stress requirements.

Dresser-Rands use of CFD simulation to optimize the sta-tionary components of a new centrifugal compressor design



The optimized design shows better pressure recovery on the surge (left) side of the pressurerecovery curve.

CFD results and physical tests provide similar estimates of compressor e ciency.

Testing shows that optimized design improves the operating range.

Performance Parameter Original Design Optimized Design

Normalized polytropic e ciency at design ow 1.000 1.001

Normalized polytropic head coe cient at design ow 1.000 1.003

Surge margin 6.1 16.0

Overload margin 13.4 12.1

accomplished several goals: This newdesign delayed the transfer of the low-momentum zone from the shroud side ofthe di user to the hub side, and it showshow proper sizing of stationary compo-nents in the early stages of the designprocess can increase the compressorsoperating range. The end result is thatDresser-Rand delivered a highly e cientcompressor with a wide operating rangein a small footprint [2].

References[1] Sorokes, J. M.; Pacheco, J. E.; Vezier, C.; Fakhri, S.

"An Analytical and Experimental Assessment of

a Di user Flow Phenomenon as a Precursor to

Stall". Proceedings of ASME Turbo Expo 2012 , 2012 ,

Volume 8: Turbomachinery, Parts A, B and C.

[2] Fakhri, S.; Sorokes, J. M.; Vezier, C.; Pacheco,

J. E. "Stationary Component Optimization andthe Resultant Improvement in the Performance

Characteristics of a Radial Compressor Stage".

Proceedings of ASME Turbo Expo 2013 , 2013 .

[3] Schi er, D. M.; Syed, A. An "Impeller Dynamic

Risk Assessment Toolkit". Proceedings of the 35th

Turbomachinery Symposium , 2006 , pp. 4954.

[4] Singh, M. P.; Vargo, J. J.; Schi er, D. M.;

Dello, J. D. "SAFE Diagram A Design and

Reliability Tool for Turbine Blading". Proceedings of

the Seventeenth Turbomachinery Symposium , 1988 ,pp. 93101.

Dresser-Randdelivered ahighly e cientcompressorwith a wideoperating rangein a smallfootprint.

http://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargers



By Chris Robinson, Managing Director, PCA Engineers Limited, Nettleham, U.K.

BEST PRACTICES

1, 2, 3TURBOCHARGED

EFFICIENCYSpecialized advanced simulation tools optimize turbochargers

for increased power and fuel efficiency.

T urbochargers are increasinglyused in automotive applications to get more power out of smallerengines. Smaller, augmented engines aremore fuel efficient and produce feweremissions without affecting a driversperception of handling and performance.The heart of a turbocharger is the com-pressor. The ideal turbocharger compres-sor is efficient over a broad operatingrange and has low inertia while simulta-neously complying with package size limi-

tations, robustness and cost constraints.PCA Engineers designs turbocharger

compressors by using multiple levels ofhighly iterative analyses, from simple 1-Dand 2-D analyses to highly sophisticated,transient, multiphysics 3-D simulations.The locus of the compressor operatingpoint within the engine can be mappedonto compressor characteristics that plotcompressor e ciency and pressure ratioagainst rotational speed and throughputof air.

PRELIMINARY ANALYSISCONFIRMS DESIGN TARGETSARE METPCA starts a turbocharger compressoroptimization with a set of design pointsfrom the key operating zones depicted inthe compressor map. The customer pro-vides the design points along with otherconstraints, such as material, manu-facturability and package size. PCAsdesigners then evaluate the perfor-mance of proposed design alternatives
http://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Industries/Automotivehttp://www.ansys.com/Industries/Automotivehttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargershttp://www.ansys.com/Industries/Industrial+Equipment+&+Rotating+Machinery/Industrial+Compressors,+Expanders+&+Turbochargers



again st these targets. Th is work is donewith ANSYS Vista CCD, a preliminarydesign tool embedded within the ANSYSWorkbench environment. Given theaerodynamic duty such as pressureratio, mass flow, and rotational speed,

and xed geometric constraints such asinducer hub diameter and vane thick-ness Vista CCD calculates a suitable 1-Dcompressor geometry and the associatedperformance map. Engineers then super-impose the map from Vista CCD onto theclient-provided targets to identify anypotential shortcomings in the prototype.The di erences between the 1-D compres -sor map and the targets are then usedto guide revisions to design parameters.This process is repeated iteratively until asatisfactory 1-D design has been achieved.From the 1-D compressor geometry, PCAsdesigners will have a good idea of how adesign ts within their range of experi -ence and what problems are likely to beencountered in improving it.

In the next phase of the design, engi-neers further re ne the geometry of theblade by launching ANSYS BladeModeler

Max power

Altitude capability

Peak torque

E c i e n c y

P r e s s u r e r a t i o

Volume ow [m3/s]

385 m/s [Mu=1.12]

A gasoline engine turbocharger compressor performance map, as measured on a test rig, is used to assess compressor suitability for a given application byshowing pressure and e ciency vs. volumetric ow rate. Red lines show approach to choke, or maximum capacity, in which volume ow becomes constant andboth pressure ratio and e ciency drop o .

that receives high pressure air from thecompressor via the di user. PCA greatlyreduced the time required to de ne thevolutes geometry by automating designiterations within ANSYS Workbench, pro-ducing a CFD-ready model of the gas-

swept surfaces in a single operation.PCAs engineers then assemble the vir-

tual design and generate the compressormap data by running a full CFD simula-tion at several ow rates for each speedof interest to verify that the new stagemeets the customer requirements. By tak-ing into account the compressors full 3-Dgeometry environment for the nal analy -sis, PCA can evaluate aspects of the designthat cannot be captured in the 1-D or 2-Danalysis, such as the e ects of tip clear -ance. Tip clearance tends not to scale lin-early, as do other dimensions, so smallcompressors have to be run at relativelyhigh clearance levels, which limits bothe ciency and range.

LONG LIFE AND ROBUSTNESSA compressors mechanical performanceis rated on whether or not it delivers the

BEST PRACTICES

from Vista CCD, de ning the basic geom-etry of the blade in that code. Next, themodel is exported to the ANSYS Vista TF2-D through ow solver. The through owstep solves the circumferentially averagedinviscid equations of motion to produce a

solution for the proposed design that canbe assessed against performance criteria.ANSYS Vista TF incorporates establishedempirical models for losses and devia-tion; it can, within a few seconds, cap-ture many of the important features of afull 3-D ow simulation. All of the work isdone within Workbench, facilitating rapidimprovements in blade design in a proc-ess that is amenable to automatic itera-tion and optimization.

FLUID DYNAMICS FOREFFICIENCYOnce the preliminary blade design iscomplete, PCAs engineers use ANSYSTurboGrid to produce a hexahedral meshfor the impeller and di user prior to full3-D computational uid dynamics (CFD)analysis. After stage analysis is complete,they design the volute, the component
http://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+BladeModeler/Features/Integrated+Initial+Sizinghttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+BladeModeler/Features/Integrated+Initial+Sizinghttp://www.ansys.com/Products/Workflow+Technology/ANSYS+Workbench+Platformhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+BladeModelerhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+Vista+TFhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+Vista+TFhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+TurboGridhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+TurboGridhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamicshttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamicshttp://www.ansys.com/Products/Workflow+Technology/ANSYS+Workbench+Platformhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+TurboGridhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+Vista+TFhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+BladeModelerhttp://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Turbomachinery+Products/ANSYS+BladeModeler/Features/Integrated+Initial+Sizing



Compressor performance maps illustrate operating regions with the greatest impact on compressor design. The dashed line zone represents idle to cruisetypical of city driving, conditions for which impeller inertia (turbo lag) is a concern. The solid line zone represents highway driving for which impeller stressesare maximized: This is the focus of most of the design e ort.

expected service life and integrity: Turbochargers are expectedto last for the life of a vehicle. Blade stress is proportional to thesquare of tip speed, so addressing mechanical issues at condi-tions that require the compressor to run faster (such as high alti-tudes) are essential in developing designs that have adequate lifeand robustness. To avoid failure by high cycle fatigue is essential,

Main targets

Capacity,integrity

important

E ciencyimportant

Map width

Max efciency,esign point

Typical output from BladeGen blade geometry designer module inANSYS BladeModeler

Typical turbocharger compressor performance targets provided toguide a compressor design

and the lowest natural frequency is usually rst ap, which is themode that would be excited if you ping the tip of the blade. This

rst vibrational mode must be at a high-enough frequency thatno vibration is triggered by harmonics from unbalanced forcesfrom the rotating shaft or ow features upstream/downstreamof the impeller.

Highway driving



An Excel macro drives the iterative geometry de nition in ANSYS Workbench. The design can beoptimized in response to design parameters chosen by the designer.

PCA performs structural analyses to test for vibrationalmodes in the same ANSYS Workbench environment, eliminat-ing the need to transfer and recreate the geometry, thus reducingthe opportunity for error. The aerodynamic pressures calculatedby CFD can be applied as loads for structural analysis to augmentthe centrifugal loads that are almost always dominant for small

turbochargers. In addition to being concerned about stress levelsand blade natural frequencies of vibration, designers must focus

BEST PRACTICES

Flow conditions at three di erent operatingpoints between surge (top) and choke (bottom).This demonstrates the performance impact of tip-clearance e ects on velocity at various ow rates.Speeds shown refer to tip speed.

385 m/s (near surge)

440 m/s (peak e ciency)

495 m/s (near choke)

on the de ection of the rotor, both radially and forward, due tothe asymmetric shape of the disc. They usually mitigate this byusing backface extension as a counterweight, reducing de ectionand bore stress.

Using ANSYS Workbench tools, PCA Engineers can optimizethe design of a turbocharger compressor long before commit-

ting to expensive prototype hardware and tests. A key advan-tage is that the complete design process, including 1-D analysis,
http://www.ansys.com/staticassets/ANSYS/staticassets/resourcelibrary/presentation/auto_conference_turbochargers_2012_Holmes_Hutchinson1.pdfhttp://www.ansys.com/staticassets/ANSYS/staticassets/resourcelibrary/presentation/auto_conference_turbochargers_2012_Holmes_Hutchinson1.pdf



The complete design process is performedwithin a single environment. Thisstreamlined approach reduces both

engineering e ort and time to market.

2-D analysis, 3-D geometry de nition andmeshing, 3-D ow simulation, and struc -tural analysis, are all performed withina single environment. This stream-lined approach reduces both engineeringe ort and time to market by eliminatingthe need to move or duplicate geometry,meshing and physical parameters infor-mation from one environment to another.

Addressing mechanical issues atconditions that require the compressorto run faster are essential in developingturbocharger designs that haveadequate life and robustness.

ANSYS Mechanical prediction of blade de ection at rst vibrational mode. This mode is engineeredso that its frequency is high enough to prevent vibration from being triggered during compressoroperation ( rst ap frequency).

Maximum stress is in the bore and is arrangedto be away from the contact zone. As the impellerruns up in speed, it leans forward at the rim andshortens axially.

PCA plans to further accelerate the designprocess by automating more of the sim-ulation through macros and scripts andby transferring its successful, auto-mated optimization experience into theWorkbench environment.
http://www.ansys.com/Products/Simulation+Technology/Structural+Mechanicshttp://www.ansys.com/Products/Simulation+Technology/Structural+Mechanics



HEALTHCARE

Heart toHeartMultiphysics systemssimulation leads to betterunderstanding of a smallerarticial heart design.

By Mark Goodin, CFD Consulting Engineer, SimuTech Group, Cleveland, U.S.A.and Michael Yaksh , MultiPhysics Consulting Engineer, Lilburn, U.S.A
http://www.ansys.com/Industries/Healthcarehttp://www.ansys.com/Products/Simulation+Technology/Systems+&+Multiphysicshttp://www.ansys.com/Products/Simulation+Technology/Systems+&+Multiphysicshttp://www.ansys.com/Industries/Healthcare



A new continuous- ow total arti -cial heart (CFTAH) is smallerand less complex than otherarti cial heart designs. It features a sin -gle moving part, the rotor, which is sus-pended by a combination of magnetic

and uid forces. This new heart is mov -ing into animal testing, which is expen-sive and time-consuming, so the cost offailure at this stage is high. To minimizethe risk and number of expensive designchanges, engineering consultants fromthe SimuTech Group are performing mul-tiphysics simulation that incorporateselectromagnetic simulation coupled withfluid flow to fully explore the CFTAHsoperation. To date, simulation has beenused to calculate the pumps hydrau-lic performance, static pressures onpump surfaces, rotor torque, rotor axialforces, and other key parameters allas part of the process of ensuring prod-uct design robustness before testing withlive animals.

POTENTIALLY LIFE-SAVINGDESIGNMore than 300,000 Americans die fromheart failure each year, and of these, upto 20 percent die while waiting for a heartdonor. Arti cial hearts have the potentialto save many of these people. But exist-ing FDA-approved devices are complex,bulky and so large that they t only 20percent of women and 50 percent of men.

Left pump Right pump

Motor

Windings

Rotating assembly

Magnets

Connectingjournal bearing

ow path

Right pumpaperture

CFTAH geometry

When right inlet pressure is high, the rotor moves to the left.

Shift to left

Right outletpressure and ow

increases

Aperture

The continuous-ow total

arti cial heartsunique designfeatures a singlemoving part: therotor, which issuspended by acombination ofmagnetic and

uid forces. When left inlet pressure is high, the rotor moves to the right.

Shift to right

Right outlet pressureand ow decreases

Left inletpressure high

Right inletpressure high

Aperture
http://www.ansys.com/Industries/Healthcare/Biomedical+Deviceshttp://www.ansys.com/Business+Initiatives/Product+Integrity+Through+Robust+Design+Optimizationhttp://www.ansys.com/Business+Initiatives/Product+Integrity+Through+Robust+Design+Optimizationhttp://www.ansys.com/Business+Initiatives/Product+Integrity+Through+Robust+Design+Optimizationhttp://www.ansys.com/Business+Initiatives/Product+Integrity+Through+Robust+Design+Optimizationhttp://www.ansys.com/Industries/Healthcare/Biomedical+Devices



The CFTAH is a more compact and simpler arti cial heart that tsmost adults and many teenagers. The device is intended for useas a bridge to a transplant as well as for permanent use to com-pletely replace a failing human heart.

The CFTAHs unique design delivers both simplicity and e -ciency. A single motor and single power cable drive the organsrotating pump assembly. Impellers supporting left and right cir-culation are mounted on opposing ends of the rotor. The rotoris radially suspended by a blood-lubricated hydrodynamic jour-nal bearing designed to minimize blood shear while maintainingstable operation. During operation, the rotating assemblyreaches a radial position in which the uid-generated hydraulic-bearing forces are balanced by electromagnetic forces exerted bythe pump motor.

During normal operation, the rotor is free to move axially,and its axial position is determined by the magnets axial restor-ing force and opposite-acting left and right pump side pressures.When the right pump pressure is higher than the left pump pres-sure, the rotating assembly is shifted by hydraulic forces to theleft. This leftward shift increases the size of the right pump aper-ture, which increases the right pumps output pressure and ow

3-D ow simulation of rotor speed contours Electromagnetics model of the motor. The rotor is shifted both axially andradially to determine the force system acting on the rotor for arbitrary rotorposition. Severe localized saturation occurs at the overhanging rotor end.

Rotor speed

rate. The increase in right pump performance raises the pressureand ow rate entering the left pump, which increases the leftpump pressure and causes the rotating assembly to shift backrightwards. This self-regulation process automatically correctsany imbalances between the right and left side pumps. If thereis a sudden change in pump pressure, the motors axial restoringforce limits the overall axial travel of the rotating assembly. Thisinnovative design eliminates the need for components that havecomplicated other arti cial heart designs, such as valves, sensorsand actuation mechanisms.

ROLE OF ELECTROMAGNETICS SIMULATIONResearchers are currently working to validate the CFTAH designin preparation for in vivo testing in animals. Simulation isneeded to capture data that cannot be collected during physicaltesting as well as to evaluate design alternatives in less time andat a lower cost than could be accomplished with physical testing.Multiphysics simulation was required because of the importanceof both electromagnetic forces and uid ow in determiningpump performance. SimuTech engineers began by developinga three-dimensional electromagnetic model in ANSYS softwareto predict the magnetic radial and axial forces and torques act-ing on the rotor for di erent axial and radial o set positions ofthe rotor with respect to the stator. The nal electromagneticmodel contained 780,000 hexahedral elements, and the teamperformed a mesh sensitivity study to validate its accuracy.

HEALTHCARE

A more-compact arti cial heart designwill t adults and teenagers, and it isless complex than other designs.
http://www.ansys.com/Products/Simulation+Technology/Electromagneticshttp://www.ansys.com/Industries/Healthcarehttp://www.ansys.com/Industries/Healthcarehttp://www.ansys.com/Products/Simulation+Technology/Electromagnetics



Angular Position Around Pump (deg)

CFTAH prototype connected to in vitro test loop

Multiphysics simulation vs. physical testing: Surface static pressures show good correlation.

Electromagnetics simulation was usedto determine the radial and axial forcesgenerated by the magnet that moves therotor toward the centerline position as afunction of the o set from the center. Thedesign depends on restoring forces to helpcontrol and limit the position of the rotor.The simulation showed that the magnetproduces a linear radial restoring force ofapproximately 1,500 Newtons per inch ofo set from the centerline of the bearing.

MODELING FLUID FLOWEngineers used the results of the electro-magnetic simulation to create a magneticforce table that they incorporated into anANSYS CFXcomputational uid dynamics(CFD) simulation as a user-de ned func -

tion. The team then used CFD to modelthe uid ow through only the journalbearing region of the pump to calculatethe rotor radial position at various rotorspeeds. As 95 percent of the radial forcesare generated in the bearing region, thisapproach provided accurate position-ing results without the need to modelthe entire pump assembly. Two di er -ent hex meshes of the bearing regionwere used to ensure that the resultswere independent of mesh density. The

ner mesh had 528,000 elements, andthe gap between the rotor and housingwas 11 elements thick, while the coarsermesh had 216,000 elements and an8-element-thick gap. The uid wasde ned as a water/glycerin mixture with

Right reservoir

Right pump

Left reservoir

Left pump

L2

L2

L3

L3

L5

L5

L in

L out

L4

L4

S t a t i c P r e s s u r e D i e r e n c e f r o m

I n l e t ( m m H g

)
http://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Fluid+Dynamics+Products/ANSYS+CFXhttp://www.ansys.c

Documents

AA V7 I3 ANSYS Advantage Turbomachinery