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-   -   GETVAR Error in Multiband Monte Carlo Radiation Simulation with Directional Source (https://www.cfd-online.com/Forums/cfx/137339-getvar-error-multiband-monte-carlo-radiation-simulation-directional-source.html)

silvan June 14, 2014 04:45

GETVAR Error in Multiband Monte Carlo Radiation Simulation with Directional Source
 
Dear experts,

I am modeling a solar reactor in CFX using the Monte Carlo ray tracing model. Simplified, the reactor is a quartz window (semitransparent) with incoming solar radiation which is followed by some kind of cavity where the reaction takes place.
There's a directional radiation source at the window. The window is modeled as participating media, the fluid inside the reactor is not (S2S only).
So far, I have managed to run many steady state simulations without any spectral dependency of the radiation (i.e. gray properties). Now, I would like to include spectral dependent properties for the window. Thus, the model is completed with the multiband model. There are two bands. The reason for the two bands is that the absorption coefficient and the refractive index of the window changes at a specific frequency and the directional source is only present in one of the bands.
Now, the issue is that the simulation runs perfectly until the monte carlo algorithm is called (every 5th iteration). Then the following error appears:

Code:

Slave:  4  Error in subroutine  CEL_GETVAR :
Slave:  4  Failed to get band definition for variable needed by Expression Language
Slave:  4  GETVAR originally called by subroutine  ASS_RADSRC_FCS

I searched all of the ANSYS support platform, the documentation, this forum but I could not make any sense of this error. I guess it has to deal with the radiation source (because of "RADSRC"). But, I am not sure about this.

Please shed some light on this issue. I would be very happy to receive useful suggestions!!!
Thanks in advance!
Silvan


For more details I enclose a snippet of the CCL:

Code:

freqhigh = clight / 0.1 [micron]
freqlow = clight / 1000 [micron]
freqmid = clight / 3.697 [micron]
abscoeff = if( Frequency >= freqmid, 4.8 [m^-1], 925.6 [m^-1])
refrindex = if( Frequency >= freqmid, 1.454, 1.265)

radiationsource3r = if( Frequency >= freqmid, -5.85678e8 [W/m^5] * r^3 + 5.42330e7 [W/m^4] * r ^2 + 4.84790e5 [W/m^3] * r + 2.09385e5 [W/m^2], 0 [W/m^2])
radiationsource3z = if( Frequency >= freqmid, if(Z Coordinate >= 0.21 [m], 1.77946e6 [W/m^3] * Z Coordinate - 3.21676e5 [W/m^2], 0 [W/m^2]), 0 [W/m^2])

...

  MATERIAL: QUARTZ
    Material Group = User
    Option = Pure Substance
    Thermodynamic State = Solid
    PROPERTIES:
      Option = General Material
      EQUATION OF STATE:
        Density = 2500 [kg m^-3]
        Molar Mass = 1.0 [kg kmol^-1]
        Option = Value
      END
      SPECIFIC HEAT CAPACITY:
        Option = Value
        Specific Heat Capacity = CpQuartz
      END
      TABLE GENERATION:
        Error Tolerance = 0.01
        Maximum Absolute Pressure = 300 [Pa]
        Maximum Points = 100
        Maximum Temperature = 2500 [K]
        Minimum Absolute Pressure = 1 [Pa]
        Minimum Temperature = 300 [K]
        Pressure Extrapolation = No
        Temperature Extrapolation = Off
      END
      THERMAL CONDUCTIVITY:
        Option = Value
        Thermal Conductivity = CondQuartz
      END
      ABSORPTION COEFFICIENT:
        Absorption Coefficient = abscoeff
        Option = Value
      END
      SCATTERING COEFFICIENT:
        Option = Value
        Scattering Coefficient = 0. [m^-1]
      END
      REFRACTIVE INDEX:
        Option = Value
        Refractive Index = refrindex
      END
    END
  END

...

  DOMAIN: window
    Coord Frame = Coord 0
    Domain Type = Solid
    Location = B564,B565,B566,B567
    BOUNDARY: fluid window interface Side 2
      Boundary Type = INTERFACE
      Location = \
        F511.565,F512.566,F513.564,F587.566,F588.566,F593.564,F595.564,F598.5\
        65,F599.565,F600.567
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Option = Conservative Interface Flux
        END
        THERMAL RADIATION:
          Option = Conservative Interface Flux
        END
      END
    END
    BOUNDARY: shield window interface Side 2
      Boundary Type = INTERFACE
      Location = F585.566,F592.564,F596.565
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Option = Conservative Interface Flux
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 0.2
          Option = Opaque
        END
      END
    END
    BOUNDARY: window bottom
      Boundary Type = WALL
      Location = F569.566,F572.565,F575.564
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Fixed Temperature = 300 [K]
          Option = Fixed Temperature
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 1.
          Option = Opaque
        END
      END
    END
    BOUNDARY: window outside cyl
      Boundary Type = WALL
      Location = F576.564,F574.565,F571.566
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Heat Transfer Coefficient = 50 [W m^-2 K^-1]
          Option = Heat Transfer Coefficient
          Outside Temperature = 300 [K]
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 1.
          Option = Opaque
        END
      END
      BOUNDARY SOURCE:
        SOURCES:
          EQUATION SOURCE: energy
            Flux = radiationloss*0.019-reradiationloss
            Option = Flux
          END
          RADIATION SOURCE: Radiation Source 1
            External Refractive Index = 1.0
            Option = Directional Radiation Flux
            Radiation Flux = radiationsource3z
            DIRECTION:
              Option = Normal to Boundary Condition
            END
          END
        END
      END
    END
    BOUNDARY: window outside spherical
      Boundary Type = WALL
      Location = F568.567,F570.566,F577.564,F573.565
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Heat Transfer Coefficient = 50 [W m^-2 K^-1]
          Option = Heat Transfer Coefficient
          Outside Temperature = 300 [K]
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 1.
          Option = Opaque
        END
      END
      BOUNDARY SOURCE:
        SOURCES:
          EQUATION SOURCE: energy
            Flux = radiationloss*0.019-reradiationloss
            Option = Flux
          END
          RADIATION SOURCE: Radiation Source 1
            External Refractive Index = 1.0
            Option = Directional Radiation Flux
            Radiation Flux = radiationsource3r
            DIRECTION:
              Option = Normal to Boundary Condition
            END
          END
        END
      END
    END
    DOMAIN MODELS:
      DOMAIN MOTION:
        Option = Stationary
      END
      MESH DEFORMATION:
        Option = None
      END
    END
    INITIALISATION:
      Option = Automatic
      INITIAL CONDITIONS:
        RADIATION INTENSITY:
          Option = Automatic
        END
        TEMPERATURE:
          Option = Automatic with Value
          Temperature = 370 [K]
        END
      END
    END
    SOLID DEFINITION: Solid 1
      Material = QUARTZ
      Option = Material Library
      MORPHOLOGY:
        Option = Continuous Solid
      END
    END
    SOLID MODELS:
      HEAT TRANSFER MODEL:
        Option = Thermal Energy
      END
      THERMAL RADIATION MODEL:
        Number of Histories = 10000000
        Option = Monte Carlo
        Radiation Transfer Mode = Participating Media
        SCATTERING MODEL:
          Option = None
        END
        SPECTRAL MODEL:
          Option = Multiband
          SPECTRAL BAND: Spectral Band 1
            Frequency Lower Limit = freqlow
            Frequency Upper Limit = freqmid
            Option = Frequency
          END
          SPECTRAL BAND: Spectral Band 2
            Frequency Lower Limit = freqmid
            Frequency Upper Limit = freqhigh
            Option = Frequency
          END
        END
      END
    END


Opaque June 14, 2014 12:03

Would mind posting the section for the thermal radiation model details on the other side of the solid interface ?

I assume you are also using two spectral bands on the neighboring domains, correct ?

silvan June 14, 2014 12:37

Thanks for your quick reply!
Here is some more of the CCL code. It is about the fluid domain adjacent to the window domain (which has been posted above).
Please let me know whether this is sufficient info. Thank you!

Yes, I am using two bands in this domain as well.

Code:

 
  DOMAIN: fluid
    Coord Frame = Coord 0
    Domain Type = Fluid
    Location = B1045,B578,B781,B782
    BOUNDARY: crucible rxn interface Side 1
      Boundary Type = INTERFACE
      Location = F661.781
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Option = Conservative Interface Flux
        END
        MASS AND MOMENTUM:
          Option = No Slip Wall
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 0.85
          Option = Opaque
        END
      END
    END
    BOUNDARY: fluid container interface Side 1
      Boundary Type = INTERFACE
      Location = F520.781,F521.781,...
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Option = Conservative Interface Flux
        END
        MASS AND MOMENTUM:
          Option = No Slip Wall
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 0.2
          Option = Opaque
        END
      END
    END
    BOUNDARY: fluid crucible cover interface Side 1
      Boundary Type = INTERFACE
      Location = F615.781,F616.781,...
        END
        MASS AND MOMENTUM:
          Option = No Slip Wall
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 0.85
          Option = Opaque
        END
      END
    END
    BOUNDARY: fluid crucible interface Side 1
      Boundary Type = INTERFACE
      Location = F525.781,F526.781,...
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Option = Conservative Interface Flux
        END
        MASS AND MOMENTUM:
          Option = No Slip Wall
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 0.85
          Option = Opaque
        END
      END
    END
    BOUNDARY: fluid exit tube interface Side 1
      Boundary Type = INTERFACE
      Location = F515.781,F765.781
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Option = Conservative Interface Flux
        END
        MASS AND MOMENTUM:
          Option = No Slip Wall
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 0.2
          Option = Opaque
        END
      END
    END
    BOUNDARY: fluid graphite wall interface Side 1
      Boundary Type = INTERFACE
      Location = F714.781,F715.781,...
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Option = Conservative Interface Flux
        END
        MASS AND MOMENTUM:
          Option = No Slip Wall
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 0.85
          Option = Opaque
        END
      END
    END
    BOUNDARY: fluid inlet
      Boundary Type = INLET
      Location = F579.578
      BOUNDARY CONDITIONS:
        FLOW DIRECTION:
          Option = Normal to Boundary Condition
        END
        FLOW REGIME:
          Option = Subsonic
        END
        HEAT TRANSFER:
          Option = Static Temperature
          Static Temperature = 300 [K]
        END
        MASS AND MOMENTUM:
          Mass Flow Rate = 2.705e-5 [kg s^-1]
          Option = Mass Flow Rate
        END
        THERMAL RADIATION:
          Option = Local Temperature
        END
      END
    END
    BOUNDARY: fluid insulation interface Side 1
      Boundary Type = INTERFACE
      Location = F740.781,F741.781,...
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Option = Conservative Interface Flux
        END
        MASS AND MOMENTUM:
          Option = No Slip Wall
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 0.7
          Option = Opaque
        END
      END
    END
    BOUNDARY: fluid outlet
      Boundary Type = OUTLET
      Location = F580.781
      BOUNDARY CONDITIONS:
        FLOW REGIME:
          Option = Subsonic
        END
        MASS AND MOMENTUM:
          Option = Average Static Pressure
          Pressure Profile Blend = 0.05
          Relative Pressure = 0 [Pa]
        END
        PRESSURE AVERAGING:
          Option = Average Over Whole Outlet
        END
        THERMAL RADIATION:
          Option = Local Temperature
        END
      END
    END
    BOUNDARY: fluid shield interface Side 1
      Boundary Type = INTERFACE
      Location = F602.782,F603.578,...
      BOUNDARY CONDITIONS:
        HEAT TRANSFER:
          Option = Conservative Interface Flux
        END
        MASS AND MOMENTUM:
          Option = No Slip Wall
        END
        THERMAL RADIATION:
          Diffuse Fraction = 1.
          Emissivity = 0.2
          Option = Opaque
        END
      END
    END
    BOUNDARY: fluid window interface Side 1
      Boundary Type = INTERFACE
      Location = F511.782,F512.782,...
          Option = Conservative Interface Flux
        END
        MASS AND MOMENTUM:
          Option = No Slip Wall
        END
        THERMAL RADIATION:
          Option = Conservative Interface Flux
        END
      END
    END
    DOMAIN MODELS:
      BUOYANCY MODEL:
        Buoyancy Reference Density = 1.784 [kg m^-3]
        Gravity X Component = 0 [m s^-2]
        Gravity Y Component = 0 [m s^-2]
        Gravity Z Component = -g
        Option = Buoyant
        BUOYANCY REFERENCE LOCATION:
          Option = Automatic
        END
      END
      DOMAIN MOTION:
        Option = Stationary
      END
      MESH DEFORMATION:
        Option = None
      END
      REFERENCE PRESSURE:
        Reference Pressure = 40 [Pa]
      END
    END
    FLUID DEFINITION: Fluid 1
      Material = Ar
      Option = Material Library
      MORPHOLOGY:
        Option = Continuous Fluid
      END
    END
    FLUID MODELS:
      COMBUSTION MODEL:
        Option = None
      END
      HEAT TRANSFER MODEL:
        Option = Thermal Energy
      END
      THERMAL RADIATION MODEL:
        Number of Histories = 10000000
        Option = Monte Carlo
        Radiation Transfer Mode = Surface to Surface
        SCATTERING MODEL:
          Option = None
        END
        SPECTRAL MODEL:
          Option = Multiband
          SPECTRAL BAND: Spectral Band 1
            Frequency Lower Limit = freqlow
            Frequency Upper Limit = freqmid
            Option = Frequency
          END
          SPECTRAL BAND: Spectral Band 2
            Frequency Lower Limit = freqmid
            Frequency Upper Limit = freqhigh
            Option = Frequency
          END
        END
      END
      TURBULENCE MODEL:
        Option = Laminar
      END
    END
    INITIALISATION:
      Option = Automatic
      INITIAL CONDITIONS:
        Velocity Type = Cartesian
        CARTESIAN VELOCITY COMPONENTS:
          Option = Automatic
        END
        RADIATION INTENSITY:
          Option = Automatic
        END
        STATIC PRESSURE:
          Option = Automatic
        END
        TEMPERATURE:
          Option = Automatic with Value
          Temperature = 1100 [K]
        END
      END
    END
  END


silvan June 16, 2014 10:49

Does anybody have an idea what I could have done wrong?
Any input is appreciated.


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