I am using a convective heat transfer model to look at the wall heat transfer coefficient as a gas flows along a pipe.
The gas I’m using is a non-standard mixture and I can customise the Material by inputting a contant viscosity, specific heat capacity and through the Prandlt number, a fluid thermal conductivity. The results I get from doing this appear reasonable.
I am though looking at quite a large temperature range and would like to change the viscosity to use the Sutherland model so that it is temperature dependent. However, when I select this option I am no longer able to specify a Prandtl number, so how does the simulation know what the thermal conductivity of the fluid is? When I run the model it appears to be applying a thermal conductivity equivalent to ta Prandtl number of 0.7, but the fluid I’m using has quite a different Prandlt number.
Am I missing something or is this a bug in the input?