[keeper]

Hi everyone,
I have a problem with defining anisotropic material in the last release of CFX.
I need to define thermal conductivity for each coordinate axis in specific value but I didn't succeed.
I tried to edit material in command editor using expression :

THERMAL CONDUCTIVITY:
Option = Orthotropic Cartesian Components
Thermal Conductivity X Component = 29 [W m^-1 K^-1]
Thermal Conductivity Y Component = 29 [W m^-1 K^-1]
Thermal Conductivity Z Component = 10 [W m^-1 K^-1]
END

But it doesn't work..

Please can anyone help me?? All suggestions are appreciated.

Thanks a lot

[Attesz]

This ccl seems to be ok, what is your error message?

[keeper]

Error message says that only allowed options are: value or kinetic theory model.
This ccl used to work in release 10 and 11 but it doesn't work in the latest release.

[keeper]

Is it possible to define this property by some expression??

Does anybody know how to define expression like f=(x,y,z) when I have defined x,y and z components??

[ghorrocks]

You can use a 3D interpolation function, if that is what you mean. If you want to set up a function like can be defined in fortran which returns a value, no this cannot be done in CEL. You will need user fortran for that.

[keeper]

I have defined thermal conductivity in x,y and z direction by using expression..

cond x = .... W m^-1 K^-1
cond y = ....W m^-1 K^-1
cond z = ....W m^-1 K^-1

And now I would like to define an expression which includes these three expressions as its components (x,y,z).

Is it possible to define it this way??

[keeper]

If somebody is interested the problem can be solved by using command line in CFX Launcher > Tools > Command line using command:

cfx5cmds -read -def ________.def -text ______.txt

which transforms def file into text file. Then by simple opening by notepad and modifying property as mentioned before you can modify this txt file and using command

cfx5cmds -write -def ________.def -text ______.txt

you will obtain modified def file with desired modifications.

Hope it will help someone.....

Good luck with your simulations

[noslip]

you could also keep your anisotropy infos in a seperate .ccl and start the solver like this:

cfx5solve.exe -def yoursimulation.def -ccl youranisomaterial.ccl


youranisomaterial.ccl would contain the entire material definition including
the "replace" command and of course the values.


LIBRARY:
&replace MATERIAL: Copper
Material Group = ...
...
...

THERMAL CONDUCTIVITY:
Option = Orthotropic Cartesian Components
Thermal Conductivity X Component = ...
...
...

END

[mactech001]

Dear keeper, noslip,

i've met with an error message while trying to perform the steps you've recommended. the error message is attached as JPEG here.

would you mind helping me to find out what else could i have done wrong in the setup please?

[keeper]

sorry I cant recognize much from your jpg. Could you attach out or txt file of your simulation please?

[serezhkin]

In case anyone still needs this, here's the ccl I received from ANSYS customer support:

LIBRARY:
&replace MATERIAL: Anyso
Material Group = User
Option = Pure Substance
Thermodynamic State = Solid
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Density = 2.645E3 [kg m^-3]
Molar Mass = 1 [kg kmol^-1]
Option = Value
END
REFERENCE STATE:
Option = Specified Point
Reference Specific Enthalpy = 0 [J kg^-1]
Reference Temperature = 25 [C]
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = 1.36E3 [J kg^-1 K^-1]
END
THERMAL CONDUCTIVITY:
Option = Orthotropic Cartesian Components
Thermal Conductivity X Component = 0.001 [W m^-1 K^-1]
Thermal Conductivity Y Component = 500 [W m^-1 K^-1]
Thermal Conductivity Z Component = 5 [W m^-1 K^-1]
#Thermal Conductivity = 175 [W m^-1 K^-1]
AXIS DEFINITION:
Option = Coordinate Axis
Rotation Axis = Coord 0.3
END
END
END
END
END

[serezhkin]

Originally Posted by keeper

If somebody is interested the problem can be solved by using command line in CFX Launcher > Tools > Command line using command:

cfx5cmds -read -def ________.def -text ______.txt

which transforms def file into text file. Then by simple opening by notepad and modifying property as mentioned before you can modify this txt file and using command

cfx5cmds -write -def ________.def -text ______.txt

you will obtain modified def file with desired modifications.

Hope it will help someone.....

Good luck with your simulations

That is a great tip, thank you very much!

[madhava317]

Thanks for the above suggestions. I have defined anisotropy as suggested. But I got the following error. Can any help in resolving this?



+--------------------------------------------------------------------+
| Writing crash recovery file |
+--------------------------------------------------------------------+

+--------------------------------------------------------------------+
| ERROR #001100279 has occurred in subroutine ErrAction. |
| Message: |
| Stopped in routine DEF_DIFMOLC |
| |
| |
| |
| |
| |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| The ANSYS CFX solver exited with return code 1. No results file |
| has been created. |
+--------------------------------------------------------------------+

[ghorrocks]

CFX does give some horrible crytic error messages sometimes.

This error might be associated with something to do with molecular diffusion. You probably have some physics defined which requires a material property (associated with diffusion I am guessing) which is not defined so it bombs out with and error.

I would simplify your model until it starts working. Then add the physics one bit at a time until it crashes - then you know what is causing the problem.

[madhava317]

The problem is simple, There is cube inside air flow. Flow in X direction. The cube has heat generatlion. First case I have defined isotropic conductivity. The problem ran fine.

Then in the second run I have introduced the anisotropic material properties as mentioned in above threads. Then I got this error after single interation. I am using CFX 11

[ghorrocks]

So it is a statement of the obvious that the problem is with the way you set the anisotropic material properties. Note that I think this is a beta feature in CFX which means they might have changed the CCL structure from what you see here. THe best way to get it working is to contact CFX support and get the CCL structure for it.

Also you will find support will probably not support V11, the current version is V14.5. So you should consider upgrading.

[Mina_Shahi]

Originally Posted by ghorrocks

You can use a 3D interpolation function, if that is what you mean. If you want to set up a function like can be defined in fortran which returns a value, no this cannot be done in CEL. You will need user fortran for that.

Hi

I want to define thermal conductivity as a function of temperature. is that possible to do in CFX? indeed i am simulating conjugated heat transfer in CFX and i have solid part which is steel and by default there is value corresponding to 25 C however i need to give the properties as a function of temperature. Is that possible ?
solid part in my case is embedded inside a combustion chamber and the flow inside that is meant for cooling therefore the temperature gradient in the solid is quite important for us if we can't define material varying by temperature this temperature gradient has no sense,.

[ghorrocks]

I am pretty sure that will work. Just try it and if it does not work it will tell you.

[Mina_Shahi]

Originally Posted by ghorrocks

I am pretty sure that will work. Just try it and if it does not work it will tell you.

I can define it as function of (x,y,z) but not as a function of temperature since the temperature is variable and it will be calculated during the simulation so i am not sure how to do that.

[ghorrocks]

Is the thermal conductivity just a function of temperature, or of other things as well? In fact, can you post the function you are trying to use?