# Flow Coefficient

## Definition - What does Flow Coefficient mean?

Flow Coefficient or coefficient of flow is the relative measure of allowing a fluid through a device. It is done for a specified opening with a pressure drop of 1 p.s.i. We can also define it as the amount of water that flows through a valve in one minute. The flow coefficient provides the general rule or a standard to compare the capacities of different valves or sizing of valves.

## Petropedia explains Flow Coefficient

The valve allowing fluid through it is more efficient than the one which faces problems with the flow process. The formula used to calculate the flow coefficient is:

**C _{v} = Q x (SG/DeltaP)^{1/2 }**

Where Q= rate of flow

C_{v} = Flow capacity or flow coefficient

SG = Specific gravity of fluid

Delta P = Pressure drop

Flow Coefficient (Cv) is different for gases, steam and for liquids. The flow coefficient and valve stroke relationship are known as the flow characteristics. At a certain stroke (or a percentage opening of the valve) a certain amount of fluid would be allowed to flow through it.