Flow thru Full Open Control valve, Liquid Service 1

[Mche]

Centrifugal pump operating at recycle flow. Minimum flow control valve (fails and) opens 100%. How to estimate flow for this situation?

Assume pump will not trip on motor overload.

Expectedly pump will operate between minimum flow point to normal operating point along its performance curve. Operating point will be decided by system pressure drop (no more by control valve). But where?

Thanks in advance.

 

[MortenA]

Find max Cv for the minflow valve

Plot dP for this value as a function of flow in the pump curve diagram.

If theres still open to the rest of the system - then this is equivalent to any "split flow" calculation that you would make. P_upstream is teh same both for the flowline and for the minflow. P down is also the same (im assuming this). So if you draw the P vs flow in the pump diagram for both the minflow valve and your system - add the two curves (minflow and system) horizontally and you get the total flow curve. Where this curve crosses you pump curve - thats your operating point

Best regards

Morten