Dear All,

I want to simulate the real exhaust gas component, the case is temperature dependent. Which thermophysical properties should I use? The multicomponent option doest concern the temperature dependent right? how about the polynomial option? will it concern the multicomponent effect?

Best regards Sakti

Multicomponent means concentration dependent, this option is suitable for multi-component mixtures. Depending on the density setting, STAR uses a constant specific heat Cv or Cp (or any other thermophysical property) for the background fluid. It also uses constant specific heats for any additional scalars present to calculate a mixture specific heat weighted according to the local concentration of each component.

Polynomial calculates the specific heat Cp (or any other thermophysical property) as a polynomial function of temperature (non-linear change of specific heat with temperature). If you click Define/Edit polynomial, it opens a special Polynomial Function Definition dialog in which polynomial coefficients may be created or edited, as necessary.

Regards

Dear Mr. Usker

Thank you for your reply, what if the properties value both concentration and temperature dependent?

regards Byan

Then your Density will be a function of pressure and temperature.

Molecular Viscosity - MultiComponent, (if your Viscosity is temperature dependent, then you have to use Sutherland. Please, refer to Star-CD Methodology.

Specific Heat - Polynomial

Conductivity - Constant or Polynomial (usually Constant, but it depends on the flow conditions)