I am trying to model an adapter roof curb for HVAC systems that usually are presented with spec sheets in USA units (more specifically CFM). However, when a flow trajectory plot is generated only SI units are available. Is it possible to change this to CFM? I know you can add a parameter from the engineering database, but it seems that only pre-defined or user defined will work which requires a formula for the specific variable.

Also, is the flow simulation advanced enough to account for basic fluid situations and equations?  As in my case, I have a confined structure with an inlet and outlet duct however there are many possible situations that could introduce transition walls from inlet to outlet. I guess my question is, can I simply define an equation goal for the pressure drop as P1-P2?

thanks