WP2.1: Pressurized Thermal Shock

Transcription

1 WP2.1: Pressurized Thermal Shock D. Lucas, P. Apanasevich, B. Niceno, C. Heib, P. Coste, M. Boucker, C. Raynauld, J. Lakehal, I. Tiselj, M. Scheuerer, D. Bestion

2 Work package 2.1: Pressurized Thermal Shock (PTS) Introduction (D. Lucas) Improved model approaches (P. Coste) Benchmark simulations on TOPFLOW-PTS (P. Apanasevich) Conclusions and recommendations (D. Lucas) Final question: Thermal loads on the RPV wall? 2

3 Work package 2.1: Pressurized Thermal Shock (PTS) Main achievements of the WP The condensation induced water hammer experiment by Martin et al. was simulated with the WAHA code Improvement of model approaches for: Turbulence models Interfacial heat transfer models hot steam inlet 1D code WAHA for condensation induced water hammer Test of capabilities of CFD-codes for PTS Benchmark on TOPFLOW-PTS experiments Benchmark on COSI experiments Validation on ROSA experiments Recommendations SLUG slug head closed end ROSA at Large Scale Test Facility 3

4 Work package 2.1: Pressurized Thermal Shock (PTS) Presentations Introduction (D. Lucas) Improved model approaches (P. Coste) Benchmark simulations on TOPFLOW-PTS (P. Apanasevich) Conclusions and recommendations (D. Lucas) 4

5 Improved model approaches TransAT ANSYS CFX 12.0 NEPTUNE_CFD Formulation One-fluid Two-fluid Two-fluid Turbulence (including buoyancy) One-fluid k-ε (URANS or V-LES) Shear Stress Transport (SST): combination of k-ε and k-ω) Two-fluid k-ε (URANS or V-LES) Wall Wall functions Wall functions Wall functions Large interface Level set AIAD detection based on the gas volume fraction α G Interface recognition based on α G w/o reconstruction Int. mom. transfer Turbulent viscosity from one-fluid k-ε Free surface drag Anisotropic friction Mass transfer model Scale Adaptative Interfacial transfer model Hughes and Duffey Large Interface Model for condensation 5

6 V-LES as tested in NURISP COSI calculations URANS (k-ε) calculation with two modifications Turbulence A decrease of the turbulent viscosity based on the comparison between a constant filter scale input by the user and the integral length scale output from the k-ε equations (Johansen et al., 2004) ν = C k² T µ ε = C ν T µ ε k² min 1; C3 3 2 k ε A consistent modification of the turbulent Reynolds number used in the closure laws 1 2 u t = k L t = min( L, ) 3 k L = or Φ 2 ε ( Two phase NEPTUNE _ CFD) ( level set TransAT) 6

7 AIAD free surface drag CFX 12.0 Int. mom. transfer Algebraic Interfacial Area Density framework (Egorov, 2004; Deendarlianto et al., 2012) Drag force: ( ) 2 F = C Aρ U U D D Mix L G ρmix = ρgαg + ρlα L α G =1 C D,D ; A D A D 6α L = d D C D,FS ; A FS A FS = α G α G = 0 6α C D,B ; A G B AB = d d B Drag coefficient: CD = fbcd,b + ffscd,fs + fdcd,d f: blending functions 2 Free surface drag coefficient (Höhne, 2009) [ αgτ G + αlτ L ] C D = ρ Mix U 2 slip L,G L,G L,G α α α ux,l,g x u y,l,g y u z,l,g z τ L,G = µ L,G + + x A FS y A FS z A FS 7

8 Anisotropic free surface friction NEPTUNE_CFD Int. mom. transfer r α qk qk LI qk J = qf ur, n F ur, t, LI ( q k ) r r Normal surface direction: bubbles and droplets drags Tangent plane : waves taken into account in roughness wall laws on liquid and gas sides G * 2 G ρ u = ρ u L * 2 L r * 2 ug = min β 2 yg, β1 + rt g Modelling of waves that can not be simulated Wind contribution (Charnock) Liquid turbulence contribution 8

9 Scale Adaptative Interfacial transfer Model TransAT Mass transfer Interphase mass transfer term in Level Set topology equation : D φ / Dt = K φ -> phase change velocity (m/s): K = m & / ρ Extension of the Surface Divergence approach :. m t t t t n K / u m/ ρ. u = C.Pr. f Re Re Banerjee et al. (2004): m=-1/2 with a turbulent Reynolds number taken in the core flow of the turbulence-generating phase TransAT (Lakehal and Labois, 2011): m=-1/4 with a turbulent Reynolds number taken right at the interface validated on the NURISP calculations of three Lim et al. (1984) tests 9

10 h ge Two-phase CFD models CFX 12.0 and NEPTUNE_CFD Mass transfer Mass transfer term deduced from a heat balance at the interface Γ 1 = h le ( T T ) + h ( T T ) Condensation mainly controlled by the liquid side Gas side model (h ge ) CFX 12.0 TOPFLOW-PTS calculations: infinite NEPTUNE_CFD 1.0.8: Jayalilleke (1969) wall law Liquid side model (h le ) CFX 12.0 TOPFLOW-PTS calculations: Hughes and Duffey model sat L H 2 ge H NEPTUNE_CFD 1.0.8: large interface model h le = 1 2 ρlc π p, L sat a 1 2 L G ε ν

11 h ge Large Interface Model for h le NEPTUNE_CFD Mass transfer Two free surface regimes : smooth and wavy Characterized by the liquid turbulence, from L-q diagram from Brochini and Peregrine, JFM 2001 A wall functionlike model for h le in large interface regions 11

12 h ge Bench: Steam Water STratified flow NEPTUNE_CFD and TransAT Lim et al. (1984) experiment Co-current condensing flow Rectangular channel z dim: 30.5 cm 10 cm Case Inlet z 0 Gas Liquid Wall Wall 910 cm 1260 cm Measurements Outlet Free m& L m& G TG kl kg ε L ε G surface (kg/s) (kg/s) ( C) (m 2.s -2 ) (m 2.s -2 ) (m 2.s -3 ) (m 2.s -3 ) 1 Smooth Smooth/wavy Wavy Wavy x CFD meshes: 2D TransAT NEPTUNE_CFD 32x130 18x410, 36x820, 72x1640 turbulence: URANS 12

13 h ge Bench: Steam Water STratified flow (cont.) TransAT URANS Smooth Transitional Wavy small Re t y+ from 5 (m8) to 20 (m2) NEPTUNE_CFD URANS default LIM options 13

14 h ge Benchmarking on COSI 3.8 NEPTUNE_CFD and TransAT COSI: thermohydraulics conditions of a PWR PTS, scale: 1/100 volume COSI 3.8: a test w/o weir Outlet Vapor inlet (co-current runs) ECC liquid inlet «Upstream» «Downstream» Vapor inlet (co-current runs) Cold water (ECC) Cold leg Weir Downcomer Downcomer 14

15 h ge COSI 3.8: sensitivity to the mesh NEPTUNE_CFD S0 G0 S1 A1 G1 S1 S2 G1 S2 A2 Mesh Г p /Г t,exp Nb of cells G0S0A G0S1A G1S2A G1S3A G1S3A S3 15

16 h ge COSI 3.8: TransAT mesh Cartesian grid Cross section: 37x37 cells 16

17 h ge COSI 3.8: URANS or V-LES NEPTUNE_CFD and TransAT TransAT Norm malized height x= x= x= -0.3 x= NEPTUNE_CFD Normalized Normalized height heigh 0 0,2 0,4 0,6 x= exp x= -0.3 x= NCFD VLES NCFD URANS 0,4 0,6 0, ,2 0,4 0,6 x= ,4 0,6 0, ,2 0,4 0,6 0,4 0,6 0, ,2 0,4 0,6 0,4 0,6 0,8 1 17

18 h ge COSI 3.8: URANS or V-LES (cont.) NEPTUNE_CFD and TransAT TransAT Norm malized height x= x= x= x= NEPTUNE_CFD Normalized Normalized height 0 0,2 0,4 0,6 x= x= x= x= ,4 0,6 0,8 1 Normalized temperature 0 0,2 0,4 0, ,4 0,6 0,8 1 Normalized temperature 0 0,2 0,4 0,6 0,4 0,6 0,8 1 Normalized temperature 0 0,2 0,4 0,6 0,4 0,6 0,8 1 Normalized temperature 18

19 h ge COSI 3.8: TransAT and NEPTUNE_CFD 19

20 h ge COSI 3.8: TransAT and NEPTUNE_CFD (cont.) 20

21 Work package 2.1: Pressurized Thermal Shock (PTS) Presentations Introduction (D. Lucas) Improved model approaches (P. Coste) Benchmark simulations on TOPFLOW-PTS experiments (P. Apanasevich) Conclusions and recommendations (D. Lucas) 21

22 TOPFLOW-PTS Experiments Pressure Vessel TOPFLOW-PTS facility Pump simulator (PS) Cold leg (CL) Downcomer WMS High-speed camera IR camera Thermo lances Reference plant: EDF CPY 900 MWe PWR Scale 1:2.5 Air-water tests without condensation Steam-water tests with condensation 22

23 Numerical Grids Neptune_CFD: IRSN-EDF grid 594,000 cells 1,500,000 cells ANSYS FLUENT: HZDR grid 865,000 cells ANSYS CFX: HZDR grid 1,450,000 cells 23

24 Neptune_CFD (IRSN, CEA): Air-water test IRSN Steam-water test CEA Two-fluid model Turbulence: k-ε model (for each phase) Large Interface Method (LIM) Transient CFX 12.0 (HZDR): Two-fluid model Turbulence: SST (for each phase) CFD Codes Algebraic Interfacial Area Density Model (AIAD) Steady state/transient FLUENT 12.0 (PSI): One momentum equation & Volume Of Fluid (VOF) approach Turbulence: LES approach (Smagorinsky model) Transient 24

25 Simulations of Air Water Reference Case 25

26 Boundary Conditions Water level in the cold leg: 50% MECC, Re_ECC=62700, θecc=0 MPS_in, Re_PS=42200, θps=1 MECC/MPS_in=1.7 MDC=MECC + MPS_in (out) θair=0.4 HZDR IRSN PSI 26

27 ECC Jet Behaviour ANSYS FLUENT ANSYS CFX Neptune_CFD Exp., HS camera HZDR IRSN PSI 27

28 Cold Leg: Water Temperature LA1 Temperature Profiles Upstream from ECC injection LA2 Temperature Profiles Upstream from ECC injection η, [-] CFX NCFD FLUENT Experiment Measurement error η, [-] CFX NCFD FLUENT Experiment Measurement error LA2 LA θ, [-] θ, [-] LA1 LA4 LA4 Temperature Profiles Upstream from ECC injection LA3 Temperature Profiles Upstream from ECC injection η, [-] CFX NCFD FLUENT Experiment Measurement error η, [-] CFX NCFD FLUENT Experiment Measurement error θ, [-] θ, [-] HZDR, IRSN, PSI 28

29 Cold Leg: Bottom Wall Temperature ANSYS FLUENT Neptune_CFD Experiment IR camera ANSYS CFX 29

30 Downcomer DCLA1 Temperature Profiles DCLA3 Temperature Profiles θ, [-] θ, [-] ζ, [-] DCLA17 Temperature Profiles CFX NCFD FLUENT Experiment Measurement error ζ, [-] CFX NCFD FLUENT Experiment Measurement error θ, [-] θ, [-] ζ, [-] DCLA20 Temperature Profiles CFX NCFD FLUENT Experiment Measurement error ζ, [-] CFX NCFD FLUENT Experiment Measurement error DCLA1 DCLA3 DCLA17 DCLA20 HZDR, IRSN, PSI 30

31 Simulations of Steam Water Reference Case 31

32 Boundary Conditions Experiment Steam_in Steam_out Steam_in Steam_out PS_in ECC DC PS_in ECC DC PS DC_out PS DC_out PS_out PS_out Water level in the cold leg: 50% MECC, Re_ECC=325,000, θecc=0 MPS_in, Re_PS=234,000, θps_in=1 MECC/MPS_in=1.7 MDC=MECC + MCond (out) HZDR PSI CEA MPS_out=MPS_in θsteam=1 32

33 Modeling of Direct Contact Condensation Neptune_CFD (CEA): Coste and Laviéville (2009) K u t t t t = 0. 35Pr Re Re 2. 14Re t 1 2 K = Pr Re u 1 8 t for smooth flows (Lakehal et al. 2008) for wavy flows FLUENT 12.0 (PSI): Hughes and Duffey (1991) K = u CFX 12.0 (HZDR): Hughes and Duffey (1991) t K = u t 2 Pr π 2 Pr π Re 4 t Re 4 t 33

34 Cold Leg η, [-] LA1 Temperature profile Upstream from ECC injection CFX_refined NCFD_coarse NCFD_refined FLUENT_coarse θ, [-] η, [-] LA2 Temperature profile Downstream from ECC injection CFX_refined NCFD_coarse NCFD_refined FLUENT_coarse θ, [-] LA1 LA2 LA4 LA3 η, [-] LA4 Temperature profile Downstream from ECC injection CFX_refined NCFD_coarse NCFD_refined FLUENT_coarse θ, [-] η, [-] LA3 Temperature profile Downstream from ECC injection CFX_refined NCFD_coarse NCFD_refined FLUENT_coarse θ, [-] HZDR PSI CEA 34

35 Cold Leg θ=0.875 Neptune_CFD ΓNCFD Γ % NCFD = = 2.25 Γ Fluent ANSYS FLUENT ANSYS CFX ΓFluent Γ % ΓCFX Fluent = = 1 Γ % Γ 1.73 CFX = = Γ Fluent Fluent 35

36 Downcomer ANSYS CFX: Inhomogeneous temperature Cold water plume θmin=0.638 θmax=0.791 θ=0.153 HZDR PSI CEA Neptune_CFD (refined grid): Homogeneous temperature θmin=0.936 θmax=0.946 θ=0.01 ANSYS FLUENT: Homogeneous temperature θmin=0.881 θmax=0.962 θ=

37 Work package 2.1: Pressurized Thermal Shock (PTS) Presentations Introduction (D. Lucas) Improved model approaches (P. Coste) Benchmark simulations on TOPFLOW-PTS (P. Apanasevich) Conclusions and recommendations (D. Lucas) 37

38 Work package 2.1: Pressurized Thermal Shock (PTS) Conclusions and Recommendations Clear benefits of a multi-scale analysis of thermal-hydraulic issues: condensation induced water hammer investigated by CFD (NURESIM) and 1D WAHA code coupled system code CFD simulation for ROSA Clear progress for two-phase PTS simulations with CFD NEPTUNE_CFD with URANS-LIM and TransAT with LEIS could simulate COSI test and several tests of Lim et al. including smooth interface and wavy interface but: pre-test simulation of steam-water TOPFLOW-PTS experiments showed clear deviations between the results obtained by different codes and models (no results with TransAT, since the data are proprietary and thus not shared with ASCOMP) Conclusions and Recommendations Further investigations are necessary to explain and minimize the inconsistencies between the codes and to identify the best models post test simulations on TOPFLOW-PTS steam-water experiments (now available) Turbulence modeling of interfacial turbulent flows should be further improved and validated for flows with wavy interface and condensation. 38

39 Work package 2.1: Pressurized Thermal Shock (PTS) Conclusions and Recommendations (cont.) The modeling of interfacial friction in case of the two-fluid URANS approach should be further improved especially for waves smaller than the grid size. Dedicated experimental data or DNS is needed to consider the influence of heat and mass transfer on friction and turbulence. Direct contact condensation approaches in TransAT (LEIS) and NEPTUNE_CFD (URANS with LIM) seem to be applicable for PTS, but validation against TOPFLOW-PTS steam-water experiments should be done as a next step. Benchmarking of different codes and models should be done since it provides valuable information on the strengths and weaknesses of the single approaches. Before reactor application for PTS simulation, it is recommended to validate a frozen version of a modelling approach at least on the following validation base: air-water Fabre et al. data, Lim et al. (1984), jet impingement data (Bonetto and Lahey, Iguchi experiments) and COSI tests. TOPFLOW-PTS and ROSA experiments should be added in the future. 39