[himalay_d]

Dear All,
Hope everyone's doing good. I am currently working on a project that involves phase change both a.) in the domain containing the working fluid and b.) in the coolant that surrounds the domain. The said fluid domains are separated by a solid copper wall. Heat from the fluid inside the copper container is extracted by the coolant fluid flowing over the said container.

Now, for simplification and ease of computation, I used R32 (difluoromethane - CH2F2), which is a general refrigerant, as the coolant that flows over the copper chamber. And within, I used Nitrogen (Peng-Robinson Real Gas) which will turn to LN2 (Liquid Nitrogen) as it looses heat to R32. R32, in turn, doesn't necessarily have to change phase.

It will be kind and helpful of you guys to help me through the following things:
1. Which multiphase model should be used? and why?
2. Should discrete phase model be used?
3. What real gas model/s should be used for nitrogen, LN2 and R32?
4. Do I need to include LN2 as a material or the Nitrogen gas (N2 with Peng Robinson) will liquify itself?

Expecting your kind responses,
HD