I am doing numerical simulation about the mixing of two fluids with different temperature by CFX-5. Both of the fluids were set to "Air Ideal Gas" with the higher temperature of 300k and the lower temperature of 150 (pressure 1 atm). But I got the averaged density at the high temperature(300K) inlet the value of 2.34kg/m^3, which should be 1.2kg/m^3 dut to the temperature and pressure. Can anybody tell me the possible reason? I am a new user of CFX.

It seems to be like you have temperature close to 150K at inlet(density 2.3528228852054585 kg/m^3)... Check your physics. Or describe your model more precisely(or send it if it is small).

Thanks, deLuther

This is my first time to use CFX (used to Fluent before), so maybe I have made some very stupid mistakes. The density at the low temperature 150K inlet is 4.33 refer to the area-averaged calculation, which is almost twice the ordinary value(similar thing happened at the 300K inlet). I just set desity to be calculated based on the ideal gas law.

I'll check it more carefully.