Hello everyone,

I am analysing a chemical reactor. I am confused with compressible ,incompressible and weakly compressible gas, and in which occation they are used. My simlation is for high pressure.I do not know how to set reference pressure, their relation with absolute pressure and how to use it for compressible incompressible and weakly compressible gas. I am in urgent need for your help. Thanks a lot for your help.

Best regards, Hx

Hi Hx,

according to the terms you use, you are user of CFX 4. Is that right? It is well described in the manual. The fully compressible flow is flow, where the density is function of temp and pressure. which is normal compressibility. For easier calculation of slow (Ma<0.3) combustion flows mainly weakly compressible version is available, where density is function of temperature only. p_abs = p_ref + p, where p is pressure actually calculated.

does it help?

Matej