Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

24 Centrifugal Pumps: Design and Application
If a new pump has the same specific speed (N s ) as the model but is to
run at a different rotating speed, head, and flow, the new pump performance
will be related to the model by:
Example
A new pump is required for 750 GPM, 600-ft head, operating at
5,000 RPM. The calculated specific speed is 1,100. The model chosen
is shown in Figure 2-1, peaks at 500 GPM, 300 ft, and operates at
3,550 RPM. Specific speed = 1,100.
From Equation 2-1:
Performance at 5,(XX) RPM can be calculated by applying the following
factors to the 3,550 RPM performance,
From Equation 2-1:
From Equation 2-2: