Studies of the ERCOFTAC Centrifugal Pump with OpenFOAM

Transcription

1 Title 1/20 Studies of the ERCOFTAC Centrifugal Pump with OpenFOAM Olivier Petit Håkan Nilsson

2 Outline Outline Geometry Boundary conditions Method and cases Comparison of numerical results with the available experimental data Outline 2/20

3 Geometry Geometry of ERCOFTAC Centrifugal Pump Positions where the results are plotted Geometry 3/20

4 Boundary conditions 4/20 Boundary conditions Radial inlet 2D 3D Axial inlet Radial oulet Radial outlet

5 Tutorial Method and Approach 5/20 Method and cases Method 2D and 3D meshes were generated using ICEM-CFD Incompressible Reynolds-Averaged Navier-Stokes equations are solved. The standard k-ε turbulence model is used. Generalized Grid Interface (GGI) is used Steady-state simulation (Frozen Rotor) Unsteady simulation (Sliding Grid) Cases 2D steady-state 2D unsteady 3D steady-state 3D unsteady

6 Tutorial 2D steady-state simulation 6/20 Set-up for the 2D steady-state simulation Schemes Convection schemes of Solvers p GAMG U linearupwind k, ε upwind smoother tolerance GaussSeidel 1.0e-08 reltol 0.05 U, k, ε smoothsolver smoother tolerance reltol 0.1 GaussSeidel 1.0e-07

7 Tutorial 2D steady-state simulation 7/20 Results for the 2D steady-state simulation Contours of the relative velocity magnitude (left) and static pressure (right).

8 Tutorial 2D unsteady simulation 8/20 Set-up for the 2D unsteady simulations Schemes Time discretization schemes Backward/Euler/Crank-Nicholson (0.2/0.5/0.8/1.0) Convection schemes of U Upwind/linearUpwind k, ε upwind Control Time step maxco 0.5/1.0/2.0/4.0 Stop time endtime 0.3 Correctors for solver turbdymfoam ncorrectors 2; noutercorrectors 1; nnonorthogonalcorrectors 1 for solver transientsimpledymfoam Solvers for p, U, k, ε, pcorr, pfinal BiCGStab ncorrectors 0; noutercorrectors 1; nnonorthogonalcorrectors 0 preconditioner reltol 0 DILU for p, U, k, ε tolerance 1.0e-07 for pcorr tolerance 1.0e-02 for pfinal tolerance 1.0e-09

9 Tutorial 2D unsteady simulation 9/20 Results for a 2D unsteady simulation (2DCN0.5L0.5T) Contours of the relative velocity magnitude (left) and static pressure (right). Animation

10 Tutorial 3D steady-state simulation 10/20 Set-up for the 3D steady-state simulation Schemes Convection schemes of Solvers p, U, k, ε GAMG U linearupwind k, ε upwind smoother tolerance GaussSeidel 1.0e-08 reltol 0.05

11 Tutorial 3D steady-state simulation 11/20 Results for the 3D steady-state simulation Contours of the relative velocity magnitude (left) and static pressure (right).

12 Tutorial 3D unsteady simulation 12/20 Set-up for the 3D unsteady simulation Schemes Time discretization schemes backward Convection schemes of U linearupwind k, ε upwind Control Time step maxco 0.5 Stop time endtime 0.3s Computing time hours < 5 days Solver transientsimpledymfoam Correctors ncorrectors 0; noutercorrectors 1; nnonorthogonalcorrectors 0 Solvers U, k, ε PBiCG p, pcorr, PCG Precoditioner DILU pfinal preconditioner DIC smoother DILU tolerance 1.0e-05 tolerance 1.0e-07 reltol for p reltol 0 reltol for pcorr, pfinal miniter 1 miniter 2 maxiter for U 4 maxiter for p 140 maxiter for k, ε maxiter for pcorr, pfinal 280

13 Tutorial 3D unsteady simulation 13/20 Results for the 3D unsteady simulation Contours of the relative velocity magnitude (left) and static pressure (right). Animation

14 2D unsteady cases 2D unsteady cases Compare the convection scheme: 2DEulerU0.5T, 2DEulerL0.5T Compare the time discretization scheme: 2DBackL0.5T, 2DEulerL0.5T, 2DCN0.5L0.5T Compare the Crank-Nicholson off-centering coefficient: 2DCN0.2L0.5T, 2DCN0.5L0.5T, 2DCN0.8L0.5T, 2DCN1.0L0.5T Compare the maximum Courant Number: 2DCN0.5L0.5T, 2DCN0.5L1.0T, 2DCN0.5L2.0T, 2DCN0.5L4.0T Compare the transient solver: 2DCN0.5L0.5T, 2DCN0.5L0.5S Comparisons 2D unsteady simulation 14/20

15 2D unsteady: Comparison of convection schemes Contours of the relative velocity magnitude Comparison of the radial velocity W r /U 2 Comparisons 2D unsteady simulation y i /G i 15/20

16 2D unsteady: Comparison of maximum Courant number Set-ups for case 2DCN0.5L0.5T, 2DCN0.5L1.0T, 2DCN0.5L2.0T and 2DCN0.5L4.0T Case maxco Time step Computing time 2DCN0.5L0.5T *10-5 s 23.9 hours 2DCN0.5L1.0T *10-5 s 11.7 hours 2DCN0.5L2.0T *10-5 s 6.4 hours 2DCN0.5L4.0T *10-5 s 3.5 hours Comparison of radial velocity W r /U 2 Comparisons 2D unsteady simulation y i /G i 16/20

17 2D unsteady: Comparison of transient solvers Contours of the relative velocity magnitude Comparison of the radial velocity W r /U 2 Comparisons 2D unsteady simulation y i /G i 17/20

18 W r /U 2 Validation of the 3D unsteady simulation Distribution of the radial velocity at the midspan position for the 3D unsteady simulation and the experimental results. y i /G i Contours of the radial velocity for different span distances for the 3D unsteady simulation (top right) and the experimental results (bottom right). Comparisons 3D unsteady simulation 18/20

19 Comparisons 3D unsteady simulation 19/20 Validation of the 3D unsteady simulation Contours of the static pressure coefficient at the midspan position for the 3D unsteady simulation (right) and experimental results (left).

20 End 20/20 Thanks Thank you for listening! Acknowledgements: Professor Ubaldi for sharing the measurement data of the ERCOFTAC Centrifugal Pump Maryse Page and Martin Beaudoin from Hydro-Quebec, Canada, and Mikko Auvinen from Aalto University, Finland, for sharing their new implementations The Swedish National Infrastructure for Computing (SNIC) and Chalmers Centre for Computational Science and Engineering (C3SE) for providing computational resources