How can the flow rate of a centrifugal pump be calculated using the motor power and the pressure at the pump outlet?

Look at the pump’s diameter; the pump’s flow rate can be roughly estimated based on its inlet.

It can only be an estimate; the error is large, and there is too much interference.

For precision, one relies on flow meters. The others can only be considered theoretical values.

1. The flow velocity in the pump outlet pipe is generally 2 to 3 meters per second; by multiplying this value by the outlet cross-sectional area, an estimate of the volumetric flow rate can be obtained. However, this method is not very accurate, as the flow velocity in the high-pressure feed pipe varies depending on the characteristics of the outlet pipeline, with the opening degree of the outlet valve being the main factor influencing it. 2. Calculate the power of the pump motor based on its current, then divide this value by the transmission efficiency, using a factor of 0.95 to 0.98, to obtain the shaft power Ne of the pump. The pump flow rate can be calculated using the formula Ne = rQH/η; all units in this formula should be in the International System of Units. r represents the specific weight of water, which is the product of water’s density and 9.806. Q is the pump flow rate, measured in cubic meters per second. H is the pump head; for approximate calculations, it can be taken as the difference between the outlet pressure and the inlet pressure, expressed in meters. η is the pump efficiency; according to pump specifications, this value is usually around 0.7. Overall, however, all the above calculations contain errors.

By referring to the pump’s performance curve, each head corresponds to a specific flow rate.

It’s too easy, so I won’t tell you