adapting openfoam for turbomachinery...

Second Second OpenFOAMOpenFOAM Workshop, Zagreb, 7Workshop, Zagreb, 7--9 June 20079 June 2007

Adapting OpenFOAM for Adapting OpenFOAM for TurbomachineryTurbomachinery ApplicationsApplications

Maryse Page and Martin BeaudoinIREQ, Hydro-Québec’s Research Institute

Second Second OpenFOAMOpenFOAM Workshop Workshop Zagreb 7Zagreb 7--9 June 20079 June 20072

Outline of the presentationOutline of the presentation

ContextOpenFOAM for hydraulic turbines

DevelopmentsHigh-performance computingGPLFuture development

Validation for hydraulic turbines


HydroHydro--QuQuéébecbec

Québec’s electric utilityPower generationTransmissionDistribution

35 GW installed capacity97% power generation based on hydroelectric resources50+ generating stations350 hydroelectric generating units


MATH: Hydraulic Turbine Analysis ModelsMATH: Hydraulic Turbine Analysis Models

Runner (rotor)

Stay vanes & guide vanes

(stator) Draft tube (diffuser)

The MATH technology:Analyze the hydraulic behaviour of hydraulic turbine by CFD


MATH technologyMATH technology

Improve the performance of hydraulic turbine by the design of tailor-made modification

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before modificationafter modification

CFD CFD analysisanalysis OnOn--site site implementationimplementation

PresPres RecoveryRecovery CoefCoefOnOn--site Turbine site Turbine EfficiencyEfficiency

modified runnermodified runner

original runneroriginal runner

modified runnermodified runner

original runneroriginal runner


MATH technologyMATH technology


OpenFOAM: new addition in OpenFOAM: new addition in ourour CFD CFD toolboxtoolbox

Open Source: potential for collaborationNo runtime licensing feesHigh quality C++ source codeSound software architecture

Object oriented design and implementationEncapsulation through librariesAlready parallelized for high-performance computing

Strong and active community with experts still actively involved in the development


Objective:

Multiple Frames of Reference (MFR)Boundary conditionsInterfaces:

– General Grid Interface (GGI)– Cyclic GGI– Mixing plane

CGNS file converters

OpenFOAM for OpenFOAM for turbomachineryturbomachinery

Developing basic steady-state capabilities for hydraulic turbines


TurbomachineryTurbomachinery modelingmodeling

Unsteadiness from relative motion of rotating and stationary parts

Requires 3D flow modeling of all the hydraulic components

Simplification by introducing:cyclic BCMFR – no relative mesh motion

For steady-state flow, more simplifications by:

neglecting transient interactionaveraging (mixing plane) between rotating/stationary parts


Multiple Frame of Multiple Frame of ReferenceReference (MFR)(MFR)

No frame change at interface between stationary and rotating domainsApplication: simpleMFRFoam

RANS formulation

rotating frame(absolute velocity)

rotating frame(relative velocity)

inertial frame(absolute velocity) 0)( =Iudiv r

( ) )(/)( III ulappgraduudiv rr νρ +−=⊗

0)( =Rudiv r( ) )(/2)( RRRR ulappgradruuudiv rrrrrrrr νρ +−=×Ω×Ω+×Ω+⊗

0)( =Iudiv r( ) )(/)( IIIR ulappgraduuudiv rrrrr νρ +−=×Ω+⊗


TestcaseTestcase: ERCOFTAC centrifugal pump: ERCOFTAC centrifugal pump

Ubaldi, Zunino, et al., LDV Investigation of the Rotor-Stator Aerodynamic Interaction in a Centrifugal Turbomachine, 1996.


MFR example: ERCOFTAC centrifugal pumpMFR example: ERCOFTAC centrifugal pump


BoundaryBoundary conditionsconditions

Walls:Rotating walls for MFRDictionary parametersEvaluated at every time iteration

draftTubeCone

type turboWallFixedValue;frameType “rotating”;velocityType “minusOmega”;omegaWallRPM 0.0;

Counter-rotating

runnerConeTurbine99

type turboWallFixedValue;frameType “fixed”;velocityType “plusOmega”;omegaWallRPM -595;

SpinningBoundary Field dictionary entryType of wall


BoundaryBoundary conditionsconditions

Inlet / outlet profilesRadial and meridian profilesFile format: CSV files (as CFX-5)Evaluated at every time iteration

inlet

type cfx5ProfileFixedValue;filePath “inlet-operA.csv”;fileFormat “CSV”;profileType “Radial”;fieldName “Velocity”;

Draft tube inlet

Boundary Field dictionary entryType of profile


InterfacesInterfaces

GGI interface:New type of interface introduced by HrvojeJasak in OpenFOAM 1.3_devBased on PatchToPatchInterpolation

– Not a sliding interface– No remeshing required for the neighbouring cells

of the interfaceGeneralization needed:

– cyclicGGI– partialGGI– mixingPlaneGGI

On-going validation


InterfacesInterfaces

Generalization of GGI using simple transformations

mixingPlaneGGIpartialGGI

cyclicGGIGGI• Not 1-to-1

abutting• Weighted

interpolation across interface

• Not 1-to-1 abutting

• Weighted interpolation

• Partial overlap with cyclic

• Circumferential averaging across the interface

99999999999999999999555555555555555555555555555559090

GGI

Outlet

Inlet

Cyclic (1-to-1)

Cyclic(1-to-1)

9090555555590

9999999999

Outlet

CyclicGGI

9999999999

Inlet

CyclicGGI

• Generalization of cyclic for not 1-to-1 abutting


Support for the CGNS file formatSupport for the CGNS file format

AIAA standard for CFD data (www.cgns.org)Archival and data exchange between toolsImporting and exporting:

Mesh, solution, BCInterface:

– Automatic reconstruction of 1-to-1 cyclic• Relaxed criteria for matching faces• Cyclic patches for non-planar surfaces

– GGI: on-going activityConverters:

– cgnsToFoam– foamToCGNS


HighHigh--performance computing with OFperformance computing with OF

Recent acquisition of a supercomputer at IREQIBM 1350 Beowulf cluster500 AMD Opteron 64-bit CPUs (1000 cores)250 x 8 GB = 2 TB of distributed RAM30 TB of fast storage (IBM GPFS parallel file system)Infiniband 4x interconnect (10 Gbps)Water-cooled rear door heat exchangers Running NPACI Rocks 4.2.1 (Centos 4.4)

OpenFOAM will be an important application for this cluster:

Optimization loopUnsteady simulationsFluid-structure interactionsLES in diffuserFree surface simulations


HighHigh--performance computing with OFperformance computing with OF


HydroHydro--QuQuéébec and the GNU GPLbec and the GNU GPL

The GNU General Public License (GPL) covers the activities of copying, distributing and modifying software source code.Users of software covered by the GPL are free or have the rights to:

Execute the software, for whatever purpose.Have access to the source code.Redistribute copies of the software, including the source code.Modify the software and distribute the modifications to the public.

The GPL does not extend to the input data nor to the results generated with GPL covered software.The GPL will automatically extend to libraries or source code linked with the original software.For more information about the GPL:

http://www.gnu.org/copyleft/gpl.html


HydroHydro--QuQuéébec and the GNU GPLbec and the GNU GPL

Hydro-Québec wants to protect the Intellectual Property coming from its R&D activities, including software source code. By default, we cannot “give away” our source code.HQ R&D CFD team wants to contribute actively to the development of OpenFOAM.We strongly believe in the added value of collaboration through Open Source development.We had to explain the ramifications of the GPL to HQ R&D managers and researchers, and we got the approval to share our work related to OpenFOAM with the community.


Future development Future development

Optimization loop with OpenFOAM as the principal computing engineBalancing the allocation of large computing resources between parallel and distributed processing

Partitioning parametersAvailable computing resources Size of problem

Source code contributions


ValidatingValidating OpenFOAM for OpenFOAM for TurbomachineryTurbomachinery

Testcases:ERCOFTAC conical diffuserTurbine 99 draft tubeDraft tube

Computational parameters:divScheme for momentum equation:

– limitedLinearV– linearUpwind

application:– simpleFoam– transientSimpleFoam


ERCOFTAC ERCOFTAC conicalconical diffuserdiffuser

Clausen, Koh and Wood, Measurementsof a swirling turbulent boundary layer developing in a conical diffuser, Exp. Thermal and Fluid Science, 1993.


ERCOFTAC ERCOFTAC conicalconical diffuserdiffuser


Turbine 99 Workshop 3Turbine 99 Workshop 3

CSII

CSIIICSIb

CSIVb

CSIa

http://www.turbine-99.org


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elbow

corner

OpenFOAMcfx-5

experiments

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cfx-5experiments

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OpenFOAMCFX-5

cprm

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OpenFOAMcfx-5

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T99T99--w3, Engineering w3, Engineering quantitiesquantities


DraftDraft tubetube

2 runner configurations:original runnermodified runner

near best efficiency for the hydraulic turbine.


DraftDraft tubetube

application: simpleFoamdivSchemes:

div(phi,U): limitedLinearV 1

original runner modified runner

residual stagnation


DraftDraft tube tube -- simpleFoamsimpleFoam

modified runner

original runner


DraftDraft tubetube

application: transientSimpleFoamdivSchemes:

div(phi,U): limitedLinearV 1ddtSchemes: Euler

original runner


DraftDraft tube tube –– transientSimpleFoamtransientSimpleFoam

unsteady phenomenaquasi-periodic


DraftDraft tube tube -- OpenFOAMOpenFOAM

timetime


DraftDraft tube tube -- OpenFOAMOpenFOAM


DraftDraft tube tube –– CFXCFX--55

adapting openfoam for turbomachinery...

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