# Thread: Flow calculation through a valve

1. ## Flow calculation through a valve

Hello all. I'm looking solve a problem with a pressure reducing valve where I'm trying to find the outlet flow from a pressure drop. My medium is diesel at 20 deg C, which I've read needs to be factored in from the Kv which is a value given for water between 5 and 40 deg C.

Inlet:
12m^3/h
40 bar

Outlet:
______m^3/h
1 bar

The valve has a Kv value of 3 or another one has a Kv of 15 for example. Which one do I choose and why? From what I've gathered so far, the Kv of 3 means 3m^3/h can pass per 1 bar pressure drop. So 39 bar pressure drop is 3 * 39 = 117m^3/h flow rate?

2. I believe that the formulas is:

GPM = Cv [ (p1 - p2) / G ]1/2

Where:

Cv = GPM that will pass through valve with pressure drop = 1 psi
G = specific gravity of the fluid,
p1 = start pressure
p2 = end pressure

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