[sasanghomi]

Dear friends,

I am looking for an option in either fluent or CFX.
In fact, I need to use Anisotropic conductivity in cylindrical coordination.(Using a tensor to set the conductivity)
However, it is not accessible in Fluent and CFX !!
I just found orthotropic conductivity in cylindrical coordination. (In Fluent)

Any ideas is appreciated deeply.

Best Regards
Sasan Ghomi

[Opaque]

Any anisotropic thermal conductivity can be diagonalized into its orthotropic components, once done you can then
1 - use Fluent: it is a released feature
2 - use CFX: it is a beta feature that had been discussed in this forum in the past

[evcelica]

Some things I have read, but not tested, and they may have changed, but keep them in mind:
1.) Coordinate axis must line up with one of the global axes
2.) All Solid-Solid Interface Mesh connection must be 1:1. (not GGI). So I believe this means you can't then use a thermal resistance model @ any solid-solid interface.

Have not done this in a while, but I believe this is how I did it:
I export the portion of the CCL file with the material definition, then modify it with my orthotropic definition. When submitting the job in solver manager, check the box for display "show advanced controls", then go to the solver tab, and use a custom executable, and choose your partial ccl file which replaces the material definition:

Example CCL below:
I'd suggest doing a test model on something simple first, and check that it works properly in all 3 directions.

LIBRARY:
&replace MATERIAL: Coils
Material Group = User
Option = Pure Substance
Thermodynamic State = Solid
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Density = 3231.42 [kg m^-3]
Molar Mass = 1.0 [kg kmol^-1]
Option = Value
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = CpCoils(T)
END
REFERENCE STATE:
Option = Specified Point
Reference Specific Enthalpy = 0 [J kg^-1]
Reference Specific Entropy = 0 [J kg^-1 K^-1]
Reference Temperature = 280[K]
END
TABLE GENERATION:
Maximum Temperature = 400 [K]
Minimum Temperature = 1 [K]
END
THERMAL CONDUCTIVITY:
Option = Orthotropic Cylindrical Components
Thermal Conductivity r Component = CondCoilRadial(T)
Thermal Conductivity Theta Component = CondCoilTheta(T)
Thermal Conductivity Axial Component = CondCoilAxial(T)
AXIS DEFINITION:
Option = Coordinate Axis
Rotation Axis = Coord 0.3
END
END
END
END
END

[sasanghomi]

Thank you for your responses.

Fluent has just orthogonal conductivity in the cylindrical coordination. (3 components)
I need 9 components in order to define the conductivity of material.
In fact, the geometry has an angle relative to the global coordination. So, I need to define a tensor to specify the conductivity of material.

Any Ideas?

Best Regards

[evcelica]

This reference has some info on general anisotropic in fluent
http://jullio.pe.kr/fluent6.1/help/html/ug/node303.htm

This won't be possible in CFX with a single material.

[Opaque]

Q: Do you know the values of the components of the tensor?

Q: I assume there are 6 (not 9) components since there should be a symmetry requirement for the tensor, correct?

Q: are these tensor values constants? or a function of another local variable, say Temperature?