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UoM-EDF Wiki Collaborative Website : sample test cases

UoM-EDF Wiki Collaborative Website : sample test cases. BENCHMARKING of codes: heated pipe. Heated vertical pipe test case. Kinetic energy. www.saturne.cfdtm.org. Temperature. - k- w models miss relaminarisation

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UoM-EDF Wiki Collaborative Website : sample test cases

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  1. UoM-EDF Wiki Collaborative Website : sample test cases 1 -

  2. BENCHMARKING of codes: heated pipe 2 - THMT 6, 2009 - H&FF Simulations for energies

  3. Heated vertical pipe test case Kinetic energy www.saturne.cfdtm.org Temperature • - k-w models miss relaminarisation • maybe too correlated to wall-distance (dominant effect of w boundary condition, and further ref to “y” in SST version, • Consistent with poor transition predictions. Ref: Keshmiri A., Addad Y. et al 3 - THMT 6, 2009 - H&FF Simulations for energies

  4. Models 4 - THMT 6, 2009 - H&FF Simulations for energies

  5. Models 5 - THMT 6, 2009 - H&FF Simulations for energies

  6. Models 6 - THMT 6, 2009 - H&FF Simulations for energies

  7. Models 7 - THMT 6, 2009 - H&FF Simulations for energies

  8. Models 8 - THMT 6, 2009 - H&FF Simulations for energies

  9. Flow through in-line tube bundles Objectives: Flow induced vibrations in heat exchangers (Lift & Drag coef.) Staggered: studied 10 years ago Current: in line Large heat exchanger => Homogeneous conditions => Periodic subset considered Mean pressure gradient Direction is in-line Re=45 000, P/D= 1.5 Embedded refinement 9 - THMT 6, 2009 - H&FF Simulations for energies

  10. In-line tube bundle • - Fully symmetric conditions, • but non-symmetric solutions • - Coanda effect ? • Star-CCM LES launched • to confirm EDF finding • (Benhamadouche et al. NURETH 11, Avignon 2005) Time averaged velocity field => 10 - THMT 6, 2009 - H&FF Simulations for energies I.Afgan@postgrad.manchester.ac.uk, with STAR-CCM

  11. Cross Flow in Tube Bundles Average Cp comparison for P/D=1.5 case Average Velocity contours at mid section for P/D=1.5 case Pseudo-average mean velocity streamlines. From left to right: P/D=1.2, P/D=1.5, P/D=1.6 and P/D=1.75 • - 4 different gap ratios was tested. P/D=1.2, 1.5, 1.6 and 1.75 • - Code Saturne and STAR CCM (I Afgan Thesis 07) 11 - THMT 6, 2009 - H&FF Simulations for energies

  12. Application to real Exchanger/ Steam Generator 12 - THMT 6, 2009 - H&FF Simulations for energies

  13. Many occurrences of Swirling Flows: • => Re Stress Transport model recommended 13 - THMT 6, 2009 - H&FF Simulations for energies

  14. Flow exiting in upper leg: • what does local probe measure? Figure 6: RSTM simulation of heterogeneities at the exit of a PWR upper plenum; scalar tracers through plenum to 4 hot leg exits (left); geometrical details as seen from actual mesh surface (right); secondary motion in hot leg cross section. (from JP Juhel and Martinez & Alvarez [17]) 14 - THMT 6, 2009 - H&FF Simulations for energies

  15. Figure 7: Turbulent shear stress across a rotating channel ( from [18]). 15 - THMT 6, 2009 - H&FF Simulations for energies

  16. Figure 8: “HYPI, FATHER” and “WATLON” T junction mixing test cases (top). Comparison of standard and advanced/”unsteady” wall functions for LES on the “WATLON” case [19]. Mean (left), rms (right) temperatures profiles and iso (centre); LES results by T. Pasutto [20]. 16 - THMT 6, 2009 - H&FF Simulations for energies

  17. Under-Resolved LES Under-resolved LES => more dangerous than coarse RANS ! => Q-LES very much needed now that Industry is into LES Channel Flow LES on structured gridat Re*=395 (Re*=y+ at centre ) % error on friction 17 - THMT 6, 2009 - H&FF Simulations for energies

  18. Better knowledge of Length scales essential for LES • Kolmogorov lengthscale • Taylor microscale • Turbulent energy L (is model): • True or Integral L: 18 - THMT 6, 2009 - H&FF Simulations for energies

  19. Integral length scales in channel flow Turbulent energy scale is easy RANS “model” but does not represent true (2 point correlation) integral scale for channel flow 1- x : streamwise 2- y : wall normal 3 – z : spanwise Solid: stream-wise separation Dashed: span-wise separation streaks Nb: longitudinal lenghtscales are divided by 2 19 -

  20. “Taylor scale” unstructured mesh Channel LES • ½ Million cells M, Re = 395, • “Wall resolved LES” • Complex geometry ? • Need Accurate precursor RANS Mean Velocity y/d 20 - THMT 6, 2009 - H&FF Simulations for energies

  21. Channel flow LES on “Taylor” mesh at Re = 395: Reynolds Stresses 21 - THMT 6, 2009 - H&FF Simulations for energies

  22. Even DNS possible with codes design for industrial Applications Budget for wall nomal velocity variance Saturne & STAR Grids (141x184x177) = 4.59 million DNS : Grid (256x193x192)= 9.48 million Budget for vv (most difficult component) 22 - THMT 6, 2009 - H&FF Simulations for energies

  23. Proper meshing for LES tedious. Ex jet injection burner Lenghtscale predicted by RANS : (k**3/2)/eps Jet => Annular co-flow Hand made grid very boring ! Need for tools for adaptive meshing 23 - THMT 6, 2009 - H&FF Simulations for energies

  24. Zonal modelling / RANS-LES coupling • LES community very active • on this topic • First idea reduce viscosity when • turbulent scale > cells • OK for Detached Eddy Simulation • (DES) • Not sufficient for turbulent • structures to appear ! • Bad transition region (kink) • where RANS viscosity • is reduced but resolved • structures are still • too weak 24 - THMT 6, 2009 - H&FF Simulations for energies

  25. Overlapping RANS - LES coupling Run both RANS and LES simulation, overlapping 2 Velocity fields, 2 viscosities, and blend only shear stress LES Overset RANS LES Velocity profile Total Turb Shear stress Resolved LES field contrib. RANS contrib. Re*=395 , 40x30x30 mesh J. Uribe, DESider Project

  26. Reynolds number non-sensitivity J. Uribe et al.

  27. 3. Besoins HPC 27 - THMT 6, 2009 - H&FF Simulations for energies

  28. 6. Industrial Applications of Advanced Simulation in CFD to Tomorrow’s Energies 28 - THMT 6, 2009 - H&FF Simulations for energies

  29. HPC roadmap: application examples (founier Club U Sat 2008 2003 2003 2006 2006 2007 2007 2010 2010 2015 2015 The whole vessel The whole vessel Consecutive to the Consecutive to the Civaux Civaux 9 fuel assemblies 9 fuel assemblies reactor reactor thermal fatigue event thermal fatigue event No experimental approach up No experimental approach up Computations enable to better Computations enable to better to now to now understand the wall thermal understand the wall thermal loading in an injection. loading in an injection. Will enable the study of side Will enable the study of side effects implied by the flow effects implied by the flow Computation with an Computation with an around neighbour fuel around neighbour fuel Knowing the root causes of the Knowing the root causes of the L.E.S. approach for L.E.S. approach for assemblies. assemblies. Þ Þ event event define a new design to define a new design to turbulent modelling turbulent modelling avoid this problem. avoid this problem. Better understanding of Better understanding of Part of a fuel assembly Part of a fuel assembly Refined mesh near the Refined mesh near the vibration phenomena and vibration phenomena and 3 grid assemblies 3 grid assemblies wall. wall. wear wear - - out of the rods. out of the rods. 6 6 6 7 7 7 8 8 8 9 9 9 10 10 10 10 10 10 cells cells cells 10 10 10 cells cells cells 10 10 10 cells cells cells 10 10 10 cells cells cells 10 10 10 cells cells cells 3.10 3.10 3.10 13 13 13 6.10 6.10 6.10 14 14 14 10 10 10 16 16 16 3.10 3.10 3.10 17 17 17 5.10 5.10 5.10 18 18 18 operations operations operations operations operations operations operations operations operations operations operations operations operations operations operations Fujistu Fujistu VPP 5000 VPP 5000 Cluster, IBM Power5 Cluster, IBM Power5 IBM Blue Gene/L IBM Blue Gene/L « « Frontier Frontier » » 30 times 30 times the power of the power of 500 times 500 times the power of the power of 1 of 4 vector processors 1 of 4 vector processors 400 processors 400 processors 8000 processors 8000 processors IBM Blue Gene/L IBM Blue Gene/L « « Frontier Frontier » » IBM Blue Gene/L IBM Blue Gene/L « « Frontier Frontier » » 2 month length computation 2 month length computation 9 days 9 days # 1 month # 1 month # 1 month # 1 month # 1 month # 1 month # 1 # 1 Gb Gb of storage of storage # 15 # 15 Gb Gb of storage of storage # 200 # 200 Gb Gb of storage of storage # 1 Tb of storage # 1 Tb of storage # 10 Tb of storage # 10 Tb of storage 2 2 Gb Gb of memory of memory 25 25 Gb Gb of memory of memory 250 250 Gb Gb of memory of memory 2,5 Tb of memory 2,5 Tb of memory 25 Tb of memory 25 Tb of memory Pre Pre - - processing not processing not parallelized parallelized … … ibid. ibid. … … … … ibid. ibid. … … Power of the computer Power of the computer Pre Pre - - processing not processing not parallelized parallelized Mesh generation Mesh generation … … ibid. ibid. … … … … ibid. ibid. … … Scalability / Solver Scalability / Solver … … ibid. ibid. … … Visualisation Visualisation 29 - Entité d'appartenance

  30. Ongoing: thermal hydraulics and vibrations of PWR fuel rods Spacer & mixer grids: hold rods, increase heat Transfer and inter channel mixing. Pb: FIV, fretting Code_SaturneLES Turbulent excitation Code_Aster Vibration 30 - THMT 6, 2009 - H&FF Simulations for energies www.framatome-anp.com, www.westinghousenuclear.com

  31. Application n°1: Impact of mixing grids effects on the water flow in nuclear fuel rod assemblies Figure 12: (12.a) Geometry of the fuel assembly. (12.b) Mesh on the wall of the mixing grids. (12.c) 3D flow around fuel rods. (12.d) velocity intensity vortices around fuel rods in a horizontal plane. 31 - THMT 6, 2009 - H&FF Simulations for energies

  32. Application n°2: Mechanical behavior of screws of core shielding Figure 13: Computation of the temperature field of bolts holding the peripheral shielding in a nuclear core. 32 - THMT 6, 2009 - H&FF Simulations for energies

  33. 33 - THMT 6, 2009 - H&FF Simulations for energies

  34. Conclusions –LES in power generation industry • LES of Industrial flow • Much more information: Fluct. thermal stresses, fatigue, acoustics, FIV • Cost-wise accessible when limited to sub-domain (synthetic turbulence) • Complex geometry possibly easier than smooth channel flow • Exploit better flexibility of professional/commercial software: • Opens new range of applications for LES • More meshing control (total cell size control from pre-simulation) • (Greater breakthrough than elaborate SGS models? ) • High Re : RANS –LES coupling, embedded LES • Cross-discipline research: • Fluids / Structure-Mech/ Materials ? • Cracks, Thermal stripping, ageing, corrosion 34 - THMT 6, 2009 - H&FF Simulations for energies

  35. Trust & Quality in LES serious issue: • 99% LES are “post-dictions”, or “explanations” • how many failed LES / no. of published LES ? (ex. 2D Hill, Ahmed body.. • errors can be much larger than in RANS • can we design next gen nuclear power plants using LES? • mesh influence tremendous, but turbulence scales not known a priori • a posteriori quality criteria known (see Q-LES workshop B. Geurts) • but trial and error most expensive with LES • do not venture outside pipe/channel flow applications? • or COLLABORATIVE work on validations in new areas on a large scale • (i.e. reporting failures is very important) 35 - THMT 6, 2009 - H&FF Simulations for energies

  36. References • Archambeau, F., Mechitoua, N. and Sakiz, M. A Finite Volume Method for the Computation of Turbulent Incompressible Flows – Industrial Applications, Int. J. Finite Volumes, Vol. 1. 2004. • Code_Saturne download URL: http://rd.edf.com/code_saturne (accessed 2009-05-11). • Testcases DB: www.saturne.cfdtm.org and http://cfd.mace.manchester.ac.uk/ercoftac/ • Rupp I., Peniguel C., Tommy-Martin M. Large Scale Finite Element Thermal Analysis of Bolts of a French PWR Core Internal Baffle Structure. 7th I. Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and SafetyNUTHOS-7, Seoul, Korea, Oct. 2008. • SYRTHES code download URL: http://rd.edf.com/syrthes (accessed 2009-05-11). • FLOMANIA – A European Initiative on Flow Physics Modelling. Haase, Aupoix, Bunge, Swamborn Eds. Notes on Numerical Fluid Mechanics Vol 94, Springer, 2006. • ERCOFTAC Best Practice Guidelines for Industrial Computational Fluid Dynamics of Single Phase Flows. V1.0, Jan 2000. URL: http://www.ercoftac.org/index.php?id=77). • Best Practice Guidelines for the use of CFD in Nuclear Reactor Safety Applications. Report NEA/CSNI/R(2007)5, 15 May 2007. Site: www.nea.fr/html/nsd/csni/cfd.htm URL: http://www.nea.fr/html/nsd/docs/2007/csni-r2007-5.pdf. (accessed 2009-05-11). • Keshmiri A., Addad Y., Cotton M.A., Laurence D. and Billard F. "Refined Eddy Viscosity Schemes and LES for Ascending Mixed Convection Flows" in Computational Heat Transfer (CHT08) Symp., Marakkech,11-16 May 2008, 1, pp. 274-279, 2008. • Durbin, P.A., Separated flow computations with the k-esp-v2 model. AIAA Journal, Vol.33(4), pp. 659-664, 1995. • Laurence D. R., Uribe J.C., Utyuzhnikov S.V., A Robust Formulation of the v2-f Model, J. Flow, Turbulence and Combustion, 73, 3-4, pp169-185, 2005. • Hanjalic, K., Popovac, M. Hadziabdic, M., A robust near- wall elliptic- relaxation eddy- viscosity model for CFD .I. J. Heat and Fluid Flow, 24, pp. 1047- 1051, 2004. 36 - THMT 6, 2009 - H&FF Simulations for energies

  37. References-2 • Manceau, R. An Improved Version of the Elliptic Blending Model. Application to Non-Rotating and Rotating Channel Flows, in 4th Symp. Turb. Shear Flow Phenomena, J.A.C. Humphrey et al., eds., Williamsburg, Virginia, USA, pp. 259-264, 2005. • Manceau, R.,Wang, M., Laurence, D. Inhomogeneity and anisotropy effects on the redistribution term in RANS modeling. J. Fluid Mech., 438, pp. 307-338, 2001. • Benhamadouche S., Laurence D. LES, Coarse LES, and Transient RANS comparison on the flow across a tube bundle. I .J. of Heat and Fluid Flow, 24, 470-479, 2003. • Benhamadouche S, Laurence D, Jarrin N, Afgan I, Moulinec C. Large Eddy Simulation of flow across in-line tube bundles. NURETH-11 paper 405, Avignon, France, Oct. 2005. • Martinez P., D. Alvarez D, Société Française d'Energie Nucléaire - SFEN ST6 meeting "CFD pour la conception et la sûreté des réacteurs", Chatou 29/04/ 2009. • Wizman, V., Laurence, D., Kanniche, M., Durbin, P., Demuren, A. Modeling near wall effects in SMC by elliptic relaxation. I. J. Heat & Fluid Flow, 17, pp. 255-266, 1996. • H. Ogawa, M. Igarashi, N. Kimura, H. Kamide Experimental study on fluid mixing phenomena in T-pipe junction with upstream elbow. NURETH 11– paper 448, 2005. • Pasutto T., Peniguel C., Stefan, Effects of the upstream elbows for thermal fatigues in PWR T Junctions using LES. ICONE-15, Nagoya, Japan, Paper 10410, 2007. • Meyers J., B. Geurts B., P. Sagaut P., Edts. Quality and Reliability of LES, ERCOFTAC Series vol. 12, Springer, 2008. • Jarrin N., Prosser R., Uribe J.C., S. Benhamadouche S., Laurence D. Reconstruction of turbulent fluctuations for hybrid RANS/LES simulations using a Synthetic-Eddy Method. I. J. Heat and Fluid Flowhttp://dx.doi.org/10.1016/j.ijheatfluidflow.2009.02.016 , 2009. • Uribe J.C., Jarrin N., Prosser R. and Laurence D., Two Velocities hybrid RANS-LES of a trailing edge flow, IUTAM Symposium "Unsteady Separated Flows and their Control" - Corfu Greece June 2007, To appear in J. Flow Turbulence and Combustion 2009. • Péniguel C., Rupp I., Juhel JP., Rolfo M., Guillaud M., Gervais N. 3D Conjugated Heat Transfer Analysis in Sodium Fast-Reactor Wire-Wrapped Fuel-Assembly, I.C. on Advances in nuclear Power Plants,ICAPP ‘09 Tokyo, Japan, Paper 9311, 2009. 37 - THMT 6, 2009 - H&FF Simulations for energies

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