[749604]

I am trying to model a valve using CFX. It is supposed to be a simple 2D simulation and involves a region of high pressure helium entering another region of air at atmospheric pressure. The high pressure (310 bar) helium enters the air region through a 3.5 mm inlet and there is a 20 mm opening in the air region. I've assumed that the helium region is just an infinite volume at 310 bar. I have a geometry for the second region which is basically a rectangle with an inlet at the bottom and an opening on the side wall.

How should I define the inlet and outlet boundary conditions? i do not know the mass flow rate or velocity at inlet so I have set the total pressure to 310 bar with reference pressure 1 atm. The outlet of the air region is given a static pressure with 0 relative pressure.

I have seen in the documentation that it is not advised to specify pressure at both the inlet and outlet but that is the only information I have.

The outside of the outlet is also at 1 atm like the air region.
The air region has a wall around it apart from the inlet and outlet.
I am also confused as to how to model the volume of the air region, I have a value for the volume but I am doing a 2D simulation in xy plane (2 elements in z-direction) so how can i relate the 2D rectangle to the volume I need?



New mesh: