Rotational Speed - Affinity Laws

The affinity laws lay down the dependency of hydraulic characteristic data of centrifugal pumps on the pumps rotational speed.

The affinity laws are applicable to friction-less systems with incompressible liquids. They are to be viewed as empirically suitable for technical application.

1st Model Law
Q2/Q1=n2/n1

2nd Model Law (Squared Law)
H2/H1=(n2/n1)2

3rd Model Law (Cubed Law)
P2/P1=(n2/n1)3

• Q = Flow
• H = Head
• P = Power Input
• n = Speed

Related Topics

• Pump H-Q Curves
• Shape Of Pump H-Q Curves

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