Pump Selection · Operating Point Back EN | ZH
Pump Engineering

Pump Selection · System Curve · Operating Point

Fit a centrifugal pump Q-H curve from 3 data points, overlay the system curve, and find the operating point. Efficiency, power, and NPSH calculated instantly.

Parameters
Pump Q-H Curve (3 points)
Efficiency Curve η(Q) (3 points)
System Curve
Static Head H_s 15.0 m
Resistance Coeff R 0.060
H_sys = H_s + R·Q² [m, m³/h]
Fluid Density ρ (kg/m³) 1000
Water: 1000 · Seawater: 1025 · Diesel: 850
Multi-pump Configuration
Operating Flow Q_op [m³/h]
Operating Head H_op [m]
Efficiency η_op [%]
Hydraulic Power P_hyd [kW]
Shaft Power P_shaft [kW]
NPSH_r Estimate [m]

Theory

Pump Q-H curve (quadratic fit): $H_p(Q) = aQ^2 + bQ + c$

System curve: $H_{sys}(Q) = H_s + R \cdot Q^2$

Operating point: $H_p(Q_{op}) = H_{sys}(Q_{op})$

$$P_{hyd} = \rho g Q H \quad [\text{W}]$$ $$P_{shaft} = \frac{P_{hyd}}{\eta}$$

Affinity laws: $\dfrac{Q_2}{Q_1}=\dfrac{n_2}{n_1}$, $\dfrac{H_2}{H_1}=\left(\dfrac{n_2}{n_1}\right)^2$, $\dfrac{P_2}{P_1}=\left(\dfrac{n_2}{n_1}\right)^3$

CAE context: Use as a pre-CFD selection tool before detailed internal flow analysis in ANSYS Fluent or OpenFOAM. Results feed into cavitation (NPSH) checks and inverter VFD energy-saving design calculations.