Effects of specific heat capacity modification - fluid/solid mesh simplifications
 

Hello everyone.
I am simulating natural convection in a multi-compartment containment using ANSYS CFX code. For better description you can imagine the containment as a cilidrically shaped vessel with a compartment on the inside that is also shaped as a cilinder.
My mesh is currently made of three domains. The first (fluid) domain is in the upper part of the containment and is used to model a helium cloud. The lower (fluid) domain contains air and steam. On the inside walls of the vessel there are heat sources which cause the occurrence of natural convection. The third domain is a solid domain which models the steel compartment inside the containment.
I have to make some modifications to the model since I want the simulation to be as simple as possible. The steel compartment is causing me some problems when using more CPUs for the simulation. The solid mesh has a small number of nodes and when I am using even 4 CPUs the percentage of overlapping nodes goes way beyond 10% and for efficient partitioning such value is not good.
My idea is to get rid of the solid domain but still leave the geometry of the fluid domains intact - the walls of the steel compartment are still being modeled. Since the steel compartment has its own specific heat capacity I must include these effects in the simulation. What I would like to know is, if it is possible that I prescribe another value for the specific heat capacity for one of the fluids so that it also covers the effects that the steel compartment has on the whole system?
For example: increasing the specific heath capacity of air or steam.

Thank you in advance to anyone who might have a clue how to help.