Studies of the ERCOFTAC Centrifugal Pump with OpenFOAM
Transcript of Studies of the ERCOFTAC Centrifugal Pump with OpenFOAM
Studies of the ERCOFTAC Centrifugal Pumpwith OpenFOAM
Shasha Xie
June 7, 2010
Title page - - Shasha Xie June 7, 2010 1/40
Outline
Outline
I Purpose and goal
I Method and approach
I Geometry
I Boundary condition
I Results
I Conclusions
Outline - - Shasha Xie June 7, 2010 2/40
Purpose and goal
I To investigate the rotor-stator interactions in the ERCOFTACCentrifugal Pump using OpenFOAM 1.5-dev.
I Carry out the unsteady simulation for both 2D and 3D modeling.
I Compare the results of the numerical solution with the experimentaldata.
Purpose and goal - - Shasha Xie June 7, 2010 3/40
Method and Approach
I MethodI 2D and 3D mesh were generated using ICEM-Hexa.I Incompressible Reynolds-Averaged Navier-Stokes equations are solved.I The standard k-ε turbulence model is used.I Generalized Grid Interface (GGI) is used:
I for the steady-state simulations.I for the unsteady simulations.
I ApproachI 2D steady-state simulationI 2D unsteady simulationI 3D steady-state simulationI 3D unsteady simulation
Method and Approach - - Shasha Xie June 7, 2010 4/40
Geometry
I Geometry of the ERCOFTAC Centrifugal Pump.
I The positions where the simulated results are plotted.
Figure: Geometry and positions for plotting the simulated results.
Geometry - - Shasha Xie June 7, 2010 5/40
Geometry
I Geometry of 2D (left) and 3D (right) model.
Geometry - - Shasha Xie June 7, 2010 6/40
Boundary conditions
I Boundary conditions.
Calculated data for the 2D cases for the 3D casesInlet Diameter D0=184 mm D0=200 mm
Z thickness Z=1 mm Z=40 mm
Flow rate Q=ϕU2πD2
24 =0.292 m3/s Q=0.292 m3/s
Inlet speed U0= QA0
= Q2πr0∗0.04=11.4 m/s U0=10.98 m/s
Rotating speed ω = 2000 rpm ω = 2000 rpm
Boundary conditions for the 2D cases for the 3D casesAt the inlet Vradial=U0 Vaxial=U0
µTµ =10 µT
µ =10
k=32U2
0 I 2=0.48735 m2/s2 (I=5%) k=0.4521 m2/s2
ε=Cµρk2
µT=
Cµρk2
µ(µT /µ)=Cµk2
ν(µT /µ)
At the outlet Average static pressure 0
Boundary conditions - - Shasha Xie June 7, 2010 7/40
2D steady-state simulation
2D steady-state simulation.
Results - 2D steady-state simulation - Shasha Xie June 7, 2010 8/40
Set-up for the 2D steady-state simulation
I Set-up for the case 2DSteady.
Schemes Convection schemes of U linearUpwind Gauss
Solvers p GAMGsmoother GaussSeideltolerance 1.0e-08relTol 0.05
U,k ,ε smoothSolversmoother GaussSeideltolerance 1.0e-07relTol 0.1
Results - 2D steady-state simulation - Shasha Xie June 7, 2010 9/40
Results for the case 2DSteady
I Contours of the relative velocity magnitude (left) and static pressure(right) for the case 2DSteady.
Results - 2D steady-state simulation - Shasha Xie June 7, 2010 10/40
Results for the case 2DSteady
I Distribution of the radial (top left), tangential (top right) velocitiesand static pressure coefficient (down) for the case 2DSteady.
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.5 1 1.5 2
Wr/U
2
yi/Gi
experimental2DSteady
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
0 0.5 1 1.5 2
Wu/
U2
yi/Gi
experimental2DSteady
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 0.5 1 1.5 2
C~p
yi/Gi
experimental2DSteady
Results - 2D steady-state simulation - Shasha Xie June 7, 2010 11/40
2D unsteady simulation
2D unsteady simulation.
I Compare the convection scheme:2DEulerU0.5T, 2DEulerL0.5T
I Compare the time discretization scheme:2DBackL0.5T, 2DEulerL0.5T, 2DCN0.5L0.5T
I Compare the Crank-Nicholson off-centering coefficient:2DCN0.2L0.5T, 2DCN0.5L0.5T, 2DCN0.8L0.5T, 2DCN1.0L0.5T
I Compare the maximum Courant Number:2DCN0.5L0.5T, 2DCN0.5L1.0T, 2DCN0.5L2.0T, 2DCN0.5L4.0T
I Compare the transient solver:2DCN0.5L0.5T, 2DCN0.5L0.5S
Results - 2D unsteady simulation - Shasha Xie June 7, 2010 12/40
Stop time is set 0.3 s
I Pressure development of 2D unsteady simulation at Probe 1 (top left),Probe 2 (top right) and Probe 3 (down left) until fully developed.
-960
-940
-920
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-880
-860
-840
0 0.05 0.1 0.15 0.2 0.25 0.3
p/rh
o
Time [s]
Probe 1
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-100
-50
0
50
0 0.05 0.1 0.15 0.2 0.25 0.3
p/rh
o
Time [s]
Probe 2
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-20
-10
0
10
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30
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0 0.05 0.1 0.15 0.2 0.25 0.3
p/rh
o
Time [s]
Probe 3
Results - 2D unsteady simulation - Shasha Xie June 7, 2010 13/40
Compare the convection scheme
I Set-up for the case 2DEulerU0.5T and 2DEulerL0.5T.Case Convection scheme
2DEulerU0.5T upwind2DEulerL0.5T linear upwind
Time discretization scheme Euler
maxCo 0.5
Solver turbDyMFoam
Correctors nCorrectors 2nOuterCorrectors 1nNonOrthogonalCorrectors 1
endTime 0.3 s
Results - 2D unsteady simulation - Convection scheme Shasha Xie June 7, 2010 14/40
Compare the convection scheme
I Contours of the relative velocity magnitude for the case2DEulerU0.5T (left) and 2DEulerL0.5T (right).
Results - 2D unsteady simulation - Convection scheme Shasha Xie June 7, 2010 15/40
Compare the convection scheme
I Distribution of the radial velocity for the case 2DEulerU0.5T and2DEulerL0.5T.
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.5 1 1.5 2
wr/U
2
yi/Gi
t/Ti=0.126
experimental2DEulerU0.5T2DEulerL0.5T
Results - 2D unsteady simulation - Convection scheme Shasha Xie June 7, 2010 16/40
Compare the time discretization scheme
I Set-up for the case 2DBackL0.5T, 2DEulerL0.5T and 2DCN0.5L0.5T.Case Time discretization scheme Computing time
2DBackL0.5T backward 22.0 hours
2DEulerL0.5T Euler 22.7 hours
2DCN0.5L0.5T Crank-Nicholson 0.5 23.9 hours
Convection scheme linearUpwind
maxCo 0.5
Solver turbDyMFoam
Correctors nCorrectors 2nOuterCorrectors 1nNonOrthogonalCorrectors 1
endTime 0.3 s
Results - 2D unsteady simulation - Time discretization scheme Shasha Xie June 7, 2010 17/40
Compare the time discretization scheme
I Distribution of radial velocity for the case 2DBackL0.5T,2DEulerL0.5T and 2DCN0.5L0.5T.
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.5 1 1.5 2
wr/U
2
yi/Gi
t/Ti=0.126
experimental2DBackL0.5T2DEulerL0.5T
2DCN0.5L0.5T
Results - 2D unsteady simulation - Time discretization scheme Shasha Xie June 7, 2010 18/40
Compare the time discretization scheme
I Contours of the relative velocity magnitude (left) and static pressure(right) for the case 2DBackL0.5T.
Results - 2D unsteady simulation - Time discretization scheme Shasha Xie June 7, 2010 19/40
Compare the time discretization scheme
I Contours of the static pressure coefficient for the case 2DBackL0.5T(left) and experimental results (right).
Results - 2D unsteady simulation - Time discretization scheme Shasha Xie June 7, 2010 20/40
Compare the Crank-Nicholson off-centering coefficient
I Set-up for the case 2DCN0.2L0.5T, 2DCN0.5L0.5T, 2DCN0.8L0.5Tand 2DCN1.0L0.5T.
Case Time discretization scheme
2DCN0.2L0.5T Crank-Nicholson 0.22DCN0.5L0.5T Crank-Nicholson 0.52DCN0.8L0.5T Crank-Nicholson 0.82DCN1.0L0.5T Crank-Nicholson 1.0
Convection scheme linearUpwind
maxCo 0.5
Solver turbDyMFoam
Correctors nCorrectors 2nOuterCorrectors 1nNonOrthogonalCorrectors 1
endTime 0.3 s
Results - 2D unsteady simulation - Crank-Nicholson coefficient Shasha Xie June 7, 2010 21/40
Compare the Crank-Nicholson off-centering coefficient
I Pressure fluctuation at Probe 1 for the case 2DCN0.2L0.5T (top left),2DCN0.5L0.5T (top right) and 2DCN0.8L0.5T (down left).
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-890
0.29 0.291 0.292 0.293 0.294 0.295
p/rh
o
Time [s]
2DCN0.2L0.5T
-940
-930
-920
-910
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-890
0.29 0.291 0.292 0.293 0.294 0.295
p/rh
o
Time [s]
2DCN0.5L0.5T
-940
-930
-920
-910
-900
-890
0.29 0.291 0.292 0.293 0.294 0.295
p/rh
o
Time [s]
2DCN0.8L0.5T
Results - 2D unsteady simulation - Crank-Nicholson coefficient Shasha Xie June 7, 2010 22/40
Compare the maximum Courant Number
I Set-up for the case 2DCN0.5L0.5T, 2DCN0.5L1.0T, 2DCN0.5L2.0Tand 2DCN0.5L4.0T.
Case maxCo Time step Computing time
2DCN0.5L0.5T 0.5 0.80 ∗ 10−5s 23.9 hours
2DCN0.5L1.0T 1.0 1.58 ∗ 10−5s 11.7 hours
2DCN0.5L2.0T 2.0 3.13 ∗ 10−5s 6.4 hours
2DCN0.5L4.0T 4.0 6.20 ∗ 10−5s 3.5 hours
Time discretization scheme Crank-Nicholson 0.5
Convection scheme linearUpwind
Solver turbDyMFoam
Correctors nCorrectors 2nOuterCorrectors 1nNonOrthogonalCorrectors 1
endTime 0.3 s
Results - 2D unsteady simulation - Maximum Courant Number Shasha Xie June 7, 2010 23/40
Compare the maximum Courant Number
I Distribution of the radial velocity for the case 2DCN0.5L0.5T,2DCN0.5L1.0T, 2DCN0.5L2.0T and 2DCN0.5L4.0T.
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.5 1 1.5 2
wr/U
2
yi/Gi
t/Ti=0.126
experimental2DCN0.5L0.5T2DCN0.5L1.0T2DCN0.5L2.0T2DCN0.5L4.0T
Results - 2D unsteady simulation - Maximum Courant Number Shasha Xie June 7, 2010 24/40
Compare the transient solver
I Set-up for the case 2DCN0.5L0.5T and 2DCN0.5L0.5S.
Case Solver nCorrectors nOuter-Correctors
nNon-Orthogonal-Correctors
2DCN0.5L0.5T turbDyMFoam 2 1 1
2DCN0.5L0.5S transientSim-pleDyMFoam
0 1 0
Time discretization scheme Crank-Nicholson 0.5
Convection scheme linearUpwind
maxCo 0.5
endTime 0.3 s
Results - 2D unsteady simulation - Transient Solver Shasha Xie June 7, 2010 25/40
Compare the transient solver
I Contours of the relative velocity magnitude for the case2DCN0.5L0.5T (left) and 2DCN0.5L0.5S (right).
Results - 2D unsteady simulation - Transient Solver Shasha Xie June 7, 2010 26/40
Compare the transient solver
I Distribution of the radial velocity for the case 2DCN0.5L0.5T and2DCN0.5L0.5S.
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.5 1 1.5 2
Wr/U
2
yi/Gi
t/Ti=0.126
experimental2DCN0.5L0.5T2DCN0.5L0.5S
Results - 2D unsteady simulation - Transient Solver Shasha Xie June 7, 2010 27/40
3D steady-state simulation
3D steady-state simulation.
Results - 3D steady-state simulation - Shasha Xie June 7, 2010 28/40
Set-up for the 3D steady-state simulation
I Set-up for the case 3DSteady.
Schemes Convection schemes of U linearUpwind Gauss
Solvers p,U,k ,ε GAMGsmoother GaussSeideltolerance 1.0e-08relTol 0.05
Results - 3D steady-state simulation - Shasha Xie June 7, 2010 29/40
Results for the case 3DSteady
I Contours of the relative velocity magnitude (left) and static pressure(right) at the midspan position for the case 3DSteady.
Results - 3D steady-state simulation - Shasha Xie June 7, 2010 30/40
Results for the case 3DSteady
I Distribution of the radial (top left), tangential (top right) velocitiesand static pressure coefficient (down) at the midspan position for thecase 3DSteady.
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.5 1 1.5 2
Wr/U
2
yi/Gi
experimental3DSteady
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
0 0.5 1 1.5 2
Wu/
U2
yi/Gi
experimental3DSteady
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 0.5 1 1.5 2
C~p
yi/Gi
experimental3DSteady
Results - 3D steady-state simulation - Shasha Xie June 7, 2010 31/40
3D unsteady simulation
3D unsteady simulation.
Results - 3D unsteady simulation - Shasha Xie June 7, 2010 32/40
Set-up for the 3D unsteady simulation
I Set-up for the case 3DBackL0.5S.
Case 3DBackL0.5S
Time discretization scheme backward
Convection scheme linearUpwind
maxCo 0.5
Stop time 0.3 s
Solver transientSimpleDyMFoam
Correctors nCorrectors 0nOuterCorrectors 1nNonOrthogonalCorrectors 0
Computing time 113.5 hours < 5 days
Results - 3D unsteady simulation - Shasha Xie June 7, 2010 33/40
Stop time is set 0.3 s
I Pressure development at Probe 1 (top left), Probe 2 (top right) andProbe 3 (down) for the 3D unsteady simulation until fully developed.
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0 0.05 0.1 0.15 0.2 0.25 0.3
p/rh
o
Time [s]
Probe 1
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0 0.05 0.1 0.15 0.2 0.25 0.3
p/rh
o
Time [s]
Probe 2
-40
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0
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0 0.05 0.1 0.15 0.2 0.25 0.3
p/rh
o
Time [s]
Probe 3
Results - 3D unsteady simulation - Shasha Xie June 7, 2010 34/40
Results for the case 3DBackL0.5S
I Contours of the relative velocity magnitude (left) and static pressure(right) at the midspan position for the case 3DBackL0.5S.
Results - 3D unsteady simulation - Shasha Xie June 7, 2010 35/40
Results for the case 3DBackL0.5S
I Distribution of the radial (top left), tangential (top right) velocitiesand static pressure coefficient (down left) at the midspan position forthe case 3DBackL0.5S.
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.5 1 1.5 2
Wr/U
2
yi/Gi
t/Ti=0.126
experimental3DBackL0.5S
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
0 0.5 1 1.5 2
Wu/
U2
yi/Gi
t/Ti=0.126
experimental3DBackL0.5S
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 0.5 1 1.5 2
C~p
yi/Gi
t/Ti=0.0
experimental3DBackL0.5S
Results - 3D unsteady simulation - Shasha Xie June 7, 2010 36/40
Results for the case 3DBackL0.5S
I Contours of the radial (left) and tangential (right) velocities fordifferent span distances for the case 3DBackL0.5S (top) andexperimental (down).
Results - 3D unsteady simulation - Shasha Xie June 7, 2010 37/40
Conclusion
I All the computational cases show some similarities with theexperimental results.
I The unsteady simulations show better prediction of the wakes thanthe steady-state simulation.
I The first-order upwind convection scheme failed in capturing the wakeeffect of the flow unsteadiness.
I Balance between short computing time and damping on the choice ofmaximum Courant Number.
I The transientSimpleDyMFoam solver shows the possibility for the 3Dunsteady simulation but still needs more validations and more testings.
Conclusion - - Shasha Xie June 7, 2010 38/40
Acknowledgements
I would like to say my thanks to
I Division of Fluid Dynamics, Department of Applied Mechanics
I Supervisors Hakan Nilsson and Olivier Petit
Acknowledgements - - Shasha Xie June 7, 2010 39/40
Thanks!
Thank you for listening.Questions?
End - - Shasha Xie June 7, 2010 40/40