Centrifugal and positive displacement pump selection and performance analysis
Featured: Hydraulic power calculation, NPSH analysis, and affinity laws
Calculate hydraulic power, shaft power, and motor power requirements
Calculate Net Positive Suction Head available and required to prevent cavitation
Calculate pump performance at different speeds or impeller diameters
Enter parameters to view pump curve
Hydraulic power (Ph) is calculated as:
Ph = (ρ × g × Q × H) / (3.6 × 106)
Shaft power (Ps) is calculated as:
Ps = Ph / ηpump
Where:
ρ = fluid density (kg/m³)
g = gravitational acceleration (9.81 m/s²)
Q = flow rate (m³/h)
H = total head (m)
ηpump = pump efficiency (decimal)
For speed changes (N1 to N2):
Q2 = Q1 × (N2/N1)
H2 = H1 × (N2/N1)2
P2 = P1 × (N2/N1)3
For impeller diameter changes (D1 to D2):
Q2 = Q1 × (D2/D1)
H2 = H1 × (D2/D1)2
P2 = P1 × (D2/D1)3
These laws are approximations and become less accurate with large changes (>20%)
Net Positive Suction Head Available (NPSHA):
NPSHA = (Ps - Pv)/(ρ × g) + hs - hf
Where:
Ps = suction pressure (Pa)
Pv = vapor pressure (Pa)
hs = static head (m)
hf = friction losses (m)
ρ = fluid density (kg/m³)
g = gravitational acceleration (9.81 m/s²)
