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June 8, 2011, 13:12 |
Water subcooled boiling
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Senior Member
Attesz
Join Date: Mar 2009
Location: Munich
Posts: 368
Rep Power: 17 |
Dear CFX users,
I have troubles with boiling simulation in CFX. The main problems are that the solver crashes when vapour generates and until crash (30-40iterations) the vapour temperatures grows up to 300000 K. I have used the default empirical terms for the boiling phenomena. The water jacket inside pressure is 6 bar, inlet temperature 85 C, wall temperature 180 degrees. Material: IAPWS water and steam, where the saturation temperature is given in tables. Any suggestion about the used models, boundaries are welcome. Thank you in advance, Attila LIBRARY: CEL: EXPRESSIONS: Gravity = -9.81[m s^-2] InletTemp = 86 [C] MaxAbsPress = OutPress+1 [atm] OutPress = 5 [bar] SaturationTemperature = Function Saturation(Absolute Pressure) SurfaceTensionCoefficient = 10^-3*Function \ SurfaceTensionCoefficient(Water.T) TempBoresValveplate = 200 [C] TempHousingValveplate = 150 [C] WallHeatTemp = 220 [C] END FUNCTION: Function Saturation Argument Units = bar Option = Interpolation Result Units = C INTERPOLATION DATA: Data Pairs = \ 0.006112,0.01,0.012271,10.00,0.023368,20.00,0.0424 17,30.00,0.073749\ ,40.00,0.12334,50.00,0.19919,60.00,0.31161,70.00,0 .47359,80.00,0.70\ 108,90.00,1.0132,100.00,1.4326,110.00,1.9854,120.0 0,2.7012,130.00,3\ .6136,140.00,4.7597,150.00,6.1804,160.00,7.9202,17 0.00,10.003,180.0\ 0,12.552,190.00,15.551,200.00,19.08,210.00,23.201, 220.00,27.979,230\ .00,33.48,240.00,39.776,250.00,46.94,260.00,55.051 ,270.00,64.191,28\ 0.00,74.448,290.00,85.917,300.00,98.697,310.00,112 .9,320.00,128.65,\ 330.00,146.08,340.00,165.37,350.00,186.74,360.00,2 10.53,370.00,221.\ 2,374.15 Extend Max = No Extend Min = No Option = One Dimensional END END FUNCTION: Function SurfaceTensionCoefficient Argument Units = C Option = Interpolation Result Units = N m^-1 INTERPOLATION DATA: Data Pairs = \ 0.01,75.6,10,74.24,20,72.78,30,71.23,40,69.61,50,6 7.93,60,66.19,70,\ 64.4,80,62.57,90,60.69,100,58.78,110,56.83,120,54. 85,130,52.83,140,\ 50.79,150,48.7,160,46.59,170,44.44,180,42.26,190,4 0.5,200,37.81,210\ ,35.53,220,33.23,230,30.9,240,28.56,250,26.19,260, 23.82,270,21.44,2\ 80,19.07,290,16.71,300,14.39,310,12.11,320,9.89,33 0,7.75,340,5.71,3\ 50,3.79,360,2.03,370,0.47,374.15,0,380,0 Extend Max = On Extend Min = No Option = One Dimensional END END END MATERIAL: Aluminium EN AC 46000 Material Group = CHT Solids Option = Pure Substance Thermodynamic State = Solid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 2650 [kg m^-3] Molar Mass = 26.98 [kg kmol^-1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 910 [J kg^-1 K^-1] END REFERENCE STATE: Option = Specified Point Reference Specific Enthalpy = 0 [J/kg] Reference Specific Entropy = 0 [J/kg/K] Reference Temperature = 25 [C] END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 120 [W m^-1 K^-1] END END END MATERIAL: Cast Iron GG25 Material Group = CHT Solids Option = Pure Substance Thermodynamic State = Solid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 7870 [kg m^-3] Molar Mass = 55.85 [kg kmol^-1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 460 [J kg^-1 K^-1] END REFERENCE STATE: Option = Specified Point Reference Specific Enthalpy = 0 [J/kg] Reference Specific Entropy = 0 [J/kg/K] Reference Temperature = 25 [C] END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 48.5 [W m^-1 K^-1] END END END MATERIAL: IAPWS STEAM Material Group = IAPWS IF97,Interphase Mass Transfer,Water Data Option = Pure Substance Thermodynamic State = Gas PROPERTIES: Option = IAPWS Library REFERENCE STATE: Option = Automatic END TABLE GENERATION: Maximum Absolute Pressure = MaxAbsPress*1.1 Maximum Points = 200 Maximum Temperature = WallHeatTemp*1.5 Minimum Absolute Pressure = 0.5 [atm] Minimum Temperature = InletTemp*0.9 Pressure Extrapolation = On Temperature Extrapolation = Yes END END END MATERIAL: IAPWS WATER Material Group = IAPWS IF97,Interphase Mass Transfer,Water Data Option = Pure Substance Thermodynamic State = Liquid PROPERTIES: Option = IAPWS Library REFERENCE STATE: Option = Automatic END TABLE GENERATION: Maximum Absolute Pressure = 2.5 [atm] Maximum Points = 200 Maximum Temperature = 550 [K] Minimum Absolute Pressure = 0.5 [atm] Minimum Temperature = 350 [K] Pressure Extrapolation = On Temperature Extrapolation = Yes END END END MATERIAL: Steel Material Group = CHT Solids Option = Pure Substance Thermodynamic State = Solid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 7854 [kg m^-3] Molar Mass = 55.85 [kg kmol^-1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 4.34E+02 [J kg^-1 K^-1] END REFERENCE STATE: Option = Specified Point Reference Specific Enthalpy = 0 [J/kg] Reference Specific Entropy = 0 [J/kg/K] Reference Temperature = 25 [C] END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 60.5 [W m^-1 K^-1] END END END MATERIAL: Water Glycol Material Group = User Option = Pure Substance Thermodynamic State = Liquid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 1045 [kg m^-3] Molar Mass = 40.9 [kg kmol^-1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 3490 [J kg^-1 K^-1] Specific Heat Type = Constant Pressure END DYNAMIC VISCOSITY: Dynamic Viscosity = 0.00105 [Pa s] Option = Value END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 0.39 [W m^-1 K^-1] END END END END FLOW: Flow Analysis 1 SOLUTION UNITS: Angle Units = [rad] Length Units = [m] Mass Units = [kg] Solid Angle Units = [sr] Temperature Units = [K] Time Units = [s] END ANALYSIS TYPE: Option = Steady State EXTERNAL SOLVER COUPLING: Option = None END END DOMAIN: FLUID_WATERJACKET Coord Frame = Coord 0 Domain Type = Fluid Location = TET_FLUID BOUNDARY: FLUID_ADIABATIC Boundary Type = WALL Location = INTER_WJ_SUPERCOOLING_GASKET_UPPER BOUNDARY CONDITIONS: HEAT TRANSFER: Option = Adiabatic END MASS AND MOMENTUM: Option = No Slip Wall END WALL CONTACT MODEL: Option = Specify Area Fraction END WALL ROUGHNESS: Option = Smooth Wall END END FLUID PAIR: Vapour | Water BOUNDARY CONDITIONS: WALL ADHESION: Option = None END WALL BOILING MODEL: Bubble Diameter Influence Factor = 2.0 Fixed Yplus for Liquid Subcooling = 250.0 Mass Source Under Relaxation = 0.1 Maximum Area Fraction of Bubble Influence = 0.5 Option = RPI Model BUBBLE DEPARTURE DIAMETER: Liquid Subcooling Scale = 45.0 [K] Maximum Departure Diameter = 1.4E-3 [m] Option = Tolubinski Kostanchuk Reference Departure Diameter = 0.6E-3 [m] END BUBBLE DETACHMENT FREQUENCY: Drag Coefficient = 1.0 Option = Terminal Velocity over Departure Diameter END BUBBLE WAITING TIME: Option = Proportional to Detachment Period Waiting Time Fraction = 0.8 END LIQUID QUENCHING HEAT TRANSFER COEFFICIENT: Option = Del Valle Kenning END WALL NUCLEATION SITE DENSITY: Option = Lemmert Chawla Power Law Index = 1.805 Reference Nucleation Site Density = 7.9384e5 [m^-2] Reference Wall Superheat = 10.0 [K] END END END END FLUID: Vapour BOUNDARY CONDITIONS: WALL CONTACT AREA: Area Fraction = 0 Option = Area Fraction END END END FLUID: Water BOUNDARY CONDITIONS: WALL CONTACT AREA: Area Fraction = 1 Option = Area Fraction END END END END BOUNDARY: FLUID_WATERJACKET Default Boundary Type = WALL Location = Primitive 2D,Primitive 2D A,Primitive 2D B,Primitive 2D \ C,Primitive 2D D,Primitive 2D E,Primitive 2D F,Primitive 2D \ G,Primitive 2D H,Primitive 2D I,Primitive 2D J,Primitive 2D \ K,Primitive 2D L,Primitive 2D M BOUNDARY CONDITIONS: HEAT TRANSFER: Option = Adiabatic END MASS AND MOMENTUM: Option = Fluid Dependent END WALL CONTACT MODEL: Option = Specify Area Fraction END WALL ROUGHNESS: Option = Smooth Wall END END FLUID PAIR: Vapour | Water BOUNDARY CONDITIONS: WALL ADHESION: Option = None END WALL BOILING MODEL: Bubble Diameter Influence Factor = 2.0 Fixed Yplus for Liquid Subcooling = 250.0 Mass Source Under Relaxation = 0.1 Maximum Area Fraction of Bubble Influence = 0.5 Option = RPI Model BUBBLE DEPARTURE DIAMETER: Liquid Subcooling Scale = 45.0 [K] Maximum Departure Diameter = 1.4E-3 [m] Option = Tolubinski Kostanchuk Reference Departure Diameter = 0.6E-3 [m] END BUBBLE DETACHMENT FREQUENCY: Drag Coefficient = 1.0 Option = Terminal Velocity over Departure Diameter END BUBBLE WAITING TIME: Option = Proportional to Detachment Period Waiting Time Fraction = 0.8 END LIQUID QUENCHING HEAT TRANSFER COEFFICIENT: Option = Del Valle Kenning END WALL NUCLEATION SITE DENSITY: Option = Lemmert Chawla Power Law Index = 1.805 Reference Nucleation Site Density = 7.9384e5 [m^-2] Reference Wall Superheat = 10.0 [K] END END END END FLUID: Vapour BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall END WALL CONTACT AREA: Area Fraction = 0 Option = Area Fraction END END END FLUID: Water BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall END WALL CONTACT AREA: Area Fraction = 1 Option = Area Fraction END END END END BOUNDARY: INLET Boundary Type = INLET Location = WATER_INLET BOUNDARY CONDITIONS: FLOW DIRECTION: Option = Normal to Boundary Condition END FLOW REGIME: Option = Subsonic END HEAT TRANSFER: Option = Static Temperature Static Temperature = InletTemp END MASS AND MOMENTUM: Mass Flow Rate = 0.24383 [kg s^-1] Option = Bulk Mass Flow Rate END TURBULENCE: Eddy Length Scale = 0.03 [m] Fractional Intensity = 0.05 Option = Intensity and Length Scale END END FLUID: Vapour BOUNDARY CONDITIONS: VOLUME FRACTION: Option = Value Volume Fraction = 0 END END END FLUID: Water BOUNDARY CONDITIONS: VOLUME FRACTION: Option = Value Volume Fraction = 1 END END END END BOUNDARY: OUTLET Boundary Type = OUTLET Location = WATER_OUTLET BOUNDARY CONDITIONS: FLOW REGIME: Option = Subsonic END MASS AND MOMENTUM: Option = Average Static Pressure Pressure Profile Blend = 0.05 Relative Pressure = OutPress END PRESSURE AVERAGING: Option = Average Over Whole Outlet END END END BOUNDARY: PIPES Boundary Type = WALL Location = WATER_INLET_PIPE,WATER_OUTLET_PIPE BOUNDARY CONDITIONS: HEAT TRANSFER: Option = Adiabatic END MASS AND MOMENTUM: Option = No Slip Wall END WALL CONTACT MODEL: Option = Use Volume Fraction END WALL ROUGHNESS: Option = Smooth Wall END END FLUID PAIR: Vapour | Water BOUNDARY CONDITIONS: WALL ADHESION: Option = None END END END END BOUNDARY: WallHeated Boundary Type = WALL Location = INTER_WJ_VALVEPLATE BOUNDARY CONDITIONS: HEAT TRANSFER: Fixed Temperature = WallHeatTemp Option = Fixed Temperature END MASS AND MOMENTUM: Option = Fluid Dependent END WALL CONTACT MODEL: Option = Specify Area Fraction END WALL ROUGHNESS: Option = Smooth Wall END END FLUID PAIR: Vapour | Water BOUNDARY CONDITIONS: WALL ADHESION: Option = None END WALL BOILING MODEL: Bubble Diameter Influence Factor = 2.0 Fixed Yplus for Liquid Subcooling = 250.0 Mass Source Under Relaxation = 0.1 Maximum Area Fraction of Bubble Influence = 0.5 Option = RPI Model BUBBLE DEPARTURE DIAMETER: Liquid Subcooling Scale = 45.0 [K] Maximum Departure Diameter = 1.4E-3 [m] Option = Tolubinski Kostanchuk Reference Departure Diameter = 0.6E-3 [m] END BUBBLE DETACHMENT FREQUENCY: Drag Coefficient = 1.0 Option = Terminal Velocity over Departure Diameter END BUBBLE WAITING TIME: Option = Proportional to Detachment Period Waiting Time Fraction = 0.8 END LIQUID QUENCHING HEAT TRANSFER COEFFICIENT: Option = Del Valle Kenning END WALL NUCLEATION SITE DENSITY: Option = Lemmert Chawla Power Law Index = 1.805 Reference Nucleation Site Density = 7.9384e5 [m^-2] Reference Wall Superheat = 10.0 [K] END END END END FLUID: Vapour BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall END WALL CONTACT AREA: Area Fraction = 0 Option = Area Fraction END END END FLUID: Water BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall END WALL CONTACT AREA: Area Fraction = 1 Option = Area Fraction END END END END DOMAIN MODELS: BUOYANCY MODEL: Buoyancy Reference Density = 0.5974 [kg m^-3] Gravity X Component = 0 [m s^-2] Gravity Y Component = 0 [m s^-2] Gravity Z Component = Gravity Option = Buoyant BUOYANCY REFERENCE LOCATION: Option = Automatic END END DOMAIN MOTION: Option = Stationary END MESH DEFORMATION: Option = None END REFERENCE PRESSURE: Reference Pressure = 1 [atm] END END FLUID DEFINITION: Vapour Material = IAPWS STEAM Option = Material Library MORPHOLOGY: Mean Diameter = 0.6 [mm] Option = Dispersed Fluid END END FLUID DEFINITION: Water Material = IAPWS WATER Option = Material Library MORPHOLOGY: Option = Continuous Fluid END END FLUID MODELS: COMBUSTION MODEL: Option = None END FLUID: Vapour FLUID BUOYANCY MODEL: Option = Density Difference END HEAT TRANSFER MODEL: Option = Thermal Energy END TURBULENCE MODEL: Option = Dispersed Phase Zero Equation END END FLUID: Water FLUID BUOYANCY MODEL: Option = Density Difference END HEAT TRANSFER MODEL: Include Viscous Dissipation Term = On Option = Thermal Energy END TURBULENCE MODEL: Option = SST BUOYANCY TURBULENCE: Option = Production Turbulent Schmidt Number = 0.9 END END TURBULENT WALL FUNCTIONS: Option = Automatic END END HEAT TRANSFER MODEL: Homogeneous Model = False Option = Fluid Dependent END THERMAL RADIATION MODEL: Option = None END TURBULENCE MODEL: Homogeneous Model = False Option = Fluid Dependent END END FLUID PAIR: Vapour | Water Surface Tension Coefficient = SurfaceTensionCoefficient INTERPHASE HEAT TRANSFER: Option = Two Resistance FLUID1 INTERPHASE HEAT TRANSFER: Option = Zero Resistance END FLUID2 INTERPHASE HEAT TRANSFER: Option = Ranz Marshall END END INTERPHASE TRANSFER MODEL: Option = Particle Model END MASS TRANSFER: Option = Phase Change PHASE CHANGE MODEL: Option = Thermal Phase Change Saturation Temperature = SaturationTemperature WALL BOILING MODEL: Bubble Diameter Influence Factor = 2.0 Fixed Yplus for Liquid Subcooling = 250.0 Mass Source Under Relaxation = 0.1 Maximum Area Fraction of Bubble Influence = 0.5 Option = RPI Model BUBBLE DEPARTURE DIAMETER: Liquid Subcooling Scale = 45.0 [K] Maximum Departure Diameter = 1.4E-3 [m] Option = Tolubinski Kostanchuk Reference Departure Diameter = 0.6E-3 [m] END BUBBLE DETACHMENT FREQUENCY: Drag Coefficient = 1.0 Option = Terminal Velocity over Departure Diameter END BUBBLE WAITING TIME: Option = Proportional to Detachment Period Waiting Time Fraction = 0.8 END LIQUID QUENCHING HEAT TRANSFER COEFFICIENT: Option = Del Valle Kenning END WALL NUCLEATION SITE DENSITY: Option = Lemmert Chawla Power Law Index = 1.805 Reference Nucleation Site Density = 7.9384e5 [m^-2] Reference Wall Superheat = 10.0 [K] END END END END MOMENTUM TRANSFER: DRAG FORCE: Option = Ishii Zuber END LIFT FORCE: Option = Tomiyama END TURBULENT DISPERSION FORCE: Option = Favre Averaged Drag Force Turbulent Dispersion Coefficient = 1.0 END VIRTUAL MASS FORCE: Option = Virtual Mass Coefficient Virtual Mass Coefficient = 0.5 END WALL LUBRICATION FORCE: Lubrication Coefficient C1 = -0.05 Lubrication Coefficient C2 = 0.01 Option = Antal END END SURFACE TENSION MODEL: Option = Continuum Surface Force Primary Fluid = Water Volume Fraction Smoothing Type = Volume-Weighted END TURBULENCE TRANSFER: ENHANCED TURBULENCE PRODUCTION MODEL: Option = Sato Enhanced Eddy Viscosity END END END INITIALISATION: Option = Automatic FLUID: Vapour INITIAL CONDITIONS: Velocity Type = Cartesian CARTESIAN VELOCITY COMPONENTS: Option = Automatic with Value U = 0 [m s^-1] V = 0 [m s^-1] W = 0 [m s^-1] END TEMPERATURE: Option = Automatic with Value Temperature = InletTemp END VOLUME FRACTION: Option = Automatic with Value Volume Fraction = 0 END END END FLUID: Water INITIAL CONDITIONS: Velocity Type = Cartesian CARTESIAN VELOCITY COMPONENTS: Option = Automatic with Value U = 0 [m s^-1] V = 0 [m s^-1] W = 0 [m s^-1] END TEMPERATURE: Option = Automatic with Value Temperature = InletTemp END TURBULENCE INITIAL CONDITIONS: Option = Low Intensity and Eddy Viscosity Ratio END VOLUME FRACTION: Option = Automatic with Value Volume Fraction = 1 END END END INITIAL CONDITIONS: STATIC PRESSURE: Option = Automatic with Value Relative Pressure = OutPress END END END MULTIPHASE MODELS: Homogeneous Model = False FREE SURFACE MODEL: Option = Standard END END END OUTPUT CONTROL: BACKUP RESULTS: Backup Results 1 File Compression Level = Default Option = Standard Output Equation Residuals = None OUTPUT FREQUENCY: Elapsed Time Interval = 2 [h] Option = Elapsed Time Interval END END |
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