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#1 |
Senior Member
Pedro Oliveira
Join Date: Feb 2018
Location: Portugal
Posts: 109
Rep Power: 8 ![]() |
I tried to define liquid water with the correspondent NASA polymonials
LIBRARY: &replace MATERIAL: NASA AGUA L Material Description = Water Vapour Material Group = Gas Phase Combustion,Interphase Mass Transfer,Water Data Object Origin = User Option = Pure Substance Thermodynamic State = Liquid PROPERTIES: Option = General Material ABSORPTION COEFFICIENT: Absorption Coefficient = 1.0 [m^-1] Option = Value END DYNAMIC VISCOSITY: Dynamic Viscosity = 0.0005 [kg m^-1 s^-1] Option = Value END EQUATION OF STATE: Density = 998 [kg m^-3] Molar Mass = 18.02 [kg kmol^-1] Option = Value END REFERENCE STATE: Option = NASA Format Reference Pressure = 1 [atm] Reference Temperature = 25 [C] END REFRACTIVE INDEX: Option = Value Refractive Index = 1.0 [m m^-1] END SCATTERING COEFFICIENT: Option = Value Scattering Coefficient = 0.0 [m^-1] END SPECIFIC HEAT CAPACITY: Option = NASA Format LOWER INTERVAL COEFFICIENTS: NASA a1 = 7.25575e01 NASA a2 = -0.662445 [K^-1] NASA a3 = 0.00256198746 [K^-2] NASA a4 = -4.36591923e-06 [K^-3] NASA a5 = 2.78178981e-09 [K^-4] NASA a6 = -41886.5499 [K] NASA a7 = -288.280137 END TEMPERATURE LIMITS: Lower Temperature = 273.150 [K] Midpoint Temperature = 1000 [K] Upper Temperature = 600.000 [K] END UPPER INTERVAL COEFFICIENTS: NASA a1 = 0 NASA a2 = 0 [K^-1] NASA a3 = 0 [K^-2] NASA a4 = 0 [K^-3] NASA a5 = 0 [K^-4] NASA a6 = 0 [K] NASA a7 = 0 END END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 0.64 [W m^-1 K^-1] END END END END and the software solver crashes with the following message: Error in subroutine CALVAR_PROP : Error calculating Thermal Expansivity GETVAR originally called by subroutine CAL_GVar Does anyone knows why? |
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#2 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,816
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You could have entered the coefficients wrongly, you could be using the model in a temperature or pressure it is not accurate for, your model could be diverging. It is going to be one of those reasons. You need to do debugging to find which.
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Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum. |
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#3 |
Senior Member
Join Date: Jun 2009
Posts: 1,850
Rep Power: 33 ![]() |
Careful with your material definition.
You have provided a constant density material, and the software is requesting the thermal expansivity, i.e. derivative of density respect to temperature and constant pressure times something else. Are you using a buoyancy model of some sort? Bousinessq model relies on the thermal expansivity, therefore my guess. |
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