pressure input, mass flow output
 

Hello! I am doing a steady state CFD on a manifold. This manifold has 4 inlets. I am doing inlet by inlet with pressure as input and trying to measure mass flow rate at the outlet. I have 4 runs - (1) Inlet 1 - applied pressure of 7000 Pa (2) Inlet 2 - applied pressure of 7000 Pa (3) Inlet 3 - applied pressure of 7000 Pa (4) Inlet 4 - applied pressure of 7000 Pa

For each run, I am measuring the mass flow at the outlet and as the runners are different in shape and length, mass flow are is different. What is the best way to describe the difference. Does it depend on length only or length, shape or what other factors can cause the change in mass flow rate.

Thanks Venu