| silvan |
June 14, 2014 03:45 |
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
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