Peng Robinson Real Gas Model
 

Hi

I am trying to validate the experimentally tested Pressure Reducer. Pressure reducer reduces the Inlet pressure of 250 bars to approx. 5 bars.

Under such high pressure air cannot be treated as Ideal Gas. Because my intuition is under such large pressure variation from Inlet to Outlet, there will be large variations in both Density and Temperature of the air. So I am thinking of using Peng Robinson real gas model in CFX.

I am using Static Pressuer at Inlet and Mass Flow at Outlet Boundary Conditions.

My question: Is this model suitable under the mentioned conditions? Further there are many properties needs to be set for this model. For Specific Heat Capacity, values of some coefficients are required( Zero Pressure Gradient coefficients for modeling variable heat capacity). How to set these values for air?

Any help is appreciated.

Regards

If you have doubts about the model then the best thing to do is to run a benchmark case at similar conditions where you have high quality known answers for. These should be easily available for something like this - you should be able to get flow though an oriface up to very high pressures and that sounds like a good benchmark case to test the accuracy of different models.