Pump Affinity Laws Calculator

STEP BY STEP

How to use pump affinity laws calculator

1. Check the input units and assumptions.
2. Review the result and example.

IN PRACTICE

Example

1500 → 1200 RPM; Q₁ = 100 m³/h; H₁ = 30 m; P₁ = 15 kW → Q₂ = 80 m³/h; H₂ = 19.2 m; P₂ = 7.68 kW.

GOOD TO KNOW

Which formula is used?

r = n₂/n₁; Q₂ = Q₁r; H₂ = H₁r²; P₂ = P₁r³. Speed-change model only. Same pump, liquid density, impeller and efficiency assumed at similar operating points. The actual duty follows the intersection with the system curve; static head, NPSH and motor limits must be checked separately. Not for positive-displacement pumps.