Temperature dependent thermal property in CFX
Trying to define a material in CFX pre with temperature dependent expression
This is what I entered :
2.9544 + 0.02*T [W m^-1 K^-1]
While running gives me error saying :
Error processing expression 'Thermal Conductivity'.
Error at position 17. Units [W m^-1 K^-1] are associated with an expression that is not dimensionless.
What should the correct expression be? Should I take out
[W m^-1 K^-1]
The problem is that T has a units associated with it. What you need to do is make sure the final result ends with a [W m^-1 K^-1]. So we would have to change it to:
2.9544 [W m^-1 K^-1] + 0.02 [W m^-1 K^-2] * T
Notice the Kelvin unit on T will cancel the one associated with the 0.02 providing the correct units. Let me know if you need further explaination.
That helped ...
After reading the messages I thought on similar lines but used it like this and that still gave me an error :
2.9544 [W m^-1 K^-1] + 0.02*T [W m^-1 K^-2]
Needs to be exactly as I have it. Again the units of [W m^-1 K^-2] must be associated with 0.02 and not as you have it where CFX is trying to associate T with [W m^-1 K^-2] when it already has units of [K].
let me explaining :D! For example, for the heat flux boundary condition, you have to build a variable called Fluxoa, like this (where t is time in [s], and Fluxoa is a heat flux in [W m^-2]:
A 1.0 [s]
B 1.0 [W m^-2]
So, the Fluxoa variable will have the [W m^-2] final heat flux unit !
with kind regards,
will this be also valid if i were to define a temperature dependent body load please?
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