Modelling closed loop liquid mixing
 

Hello everyone,

I want to investigate the mixing of two liquids, one coming from a mainline and the other from venturi injectors. I know all the pressures and flows of the system.

My problem is that I don't know how to imitate the effect of a pump in the middle of the system. As you see in the figure, the pressure at the inlet of the venturi injectors is 3 bars, then drops at 0.5 and joins another flow to go to the pump and reach 6.5 bars.

If I set the BC of the inlet to the specific mass flow rate, then the pressure is too low. Then I added a fan BC to imitate the pump, but then because the outlet has higher pressure the flow goes the "wrong" direction and the pressure is too high.

Any ideas?
Thanks!

http://i65.tinypic.com/mlpm6s.jpg
http://i67.tinypic.com/2dtn4ap.jpg