CFD Online Discussion Forums - constant volume pump bc udf

I need to create a boundary that works like a constant volume pump. Meaning at a multiphase outlet a fixed volume flow rate has to be removed (indiscriminate of phase) . I have done this manually using a pressure outlet with a negative gauge pressure but I want a automatic version that reads in the volume flow rate out of the boundary then adjusts the gauge pressure to achieve a pre defined volume flow rate. Has anyone done anything simlar or has an simlar example udf.

Thanks Adam