The discharge coefficient is a characteristic non-dimensional factor of the valve, which is used to calculate the flow rate (Q) when the valve discharges the fluid from a tank or reservoir (Δh) to the environment.

(liquids)
Q: Flow rate
Δh: Head loss
D: Pipe diameter
C: Discharge Coefficient
g: gravity

Go to online calculation of the discharge coefficient C

Unlike the flow coefficient, discharge coefficient is dimensionless and almost constant value for any diameter of a single model. Manufacturers often provide the discharge coefficient of the valve in fully open position, maximum discharge.

For the same high of fluid in the reservoir, higher is the discharge coefficient, higher is the flow rate, therefore the reservoir can be voided at shorter time.

Fixed cone valves are discharge valves and manufacturers use to provide the discharge coefficient instead of the flow coefficient. The discharge coefficient value is between C=0,75 and C=0,85.

There are equations to convert the discharge coefficient to the flow coefficient, and diameter is a parameter to introduce as the flow coefficient varies on it.

Go to calculate conversion between flow discharge C and flow coefficient Kv y Cv