Centrifugal-pump performance scaling when impeller speed or diameter changes - Q ∝ n, H ∝ n², P ∝ n³.
Formula
$$ \frac{Q_2}{Q_1} = \frac{n_2}{n_1}, \ \frac{H_2}{H_1} = \left(\frac{n_2}{n_1}\right)^2, \ \frac{P_2}{P_1} = \left(\frac{n_2}{n_1}\right)^3 $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $Q, H, P$ | Flow, head, power | - | pump curves |
| $n$ | Impeller speed | rpm | VFD set-point |
Sources
- Hydraulic Institute Standards.