AutoEngCalc - Engineering Calculators

Pump Affinity Laws Calculator

Predict pump performance changes with speed and impeller diameter variations. Analyze flow, head, and power relationships according to affinity laws.

Pump Affinity: N1=1750 RPM, D1=200mm
Q2 = 82.3 m³/h

Pump Affinity Laws Calculator

Analyze the effects of speed and impeller diameter changes on pump performance

Affinity Laws Calculator

Calculate pump performance changes based on speed and impeller diameter

RPM
Typical range: 1000 - 3600 RPM
RPM
Leave blank if no speed change
mm
Common sizes: 150, 200, 250, 300 mm
mm
Leave blank if no diameter change
m³/h
m
kW

System Curve Analysis

Analyze the system curve for pump performance

m
H = Hstatic + k × Q2

Where H is total head (m), Q is flow rate (m³/h)

Performance Comparison

Compare performance changes due to speed, diameter, and combined effects

Speed Change

Ratio: -

Diameter Change

Ratio: -

Combined Change

Ratio: -

Pump Performance Results

New Flow Rate

-

m³/h

New Head

-

m

New Power

-

kW

Speed Ratio

-

N2/N1

Diameter Ratio

-

D2/D1

Flow Ratio

-

Q2/Q1

Power Ratio

-

P2/P1

Impeller Inlet Outlet
Pump Diagram - Impeller Size: - mm

Pump Affinity Laws Reference

Speed Changes

When pump speed changes (RPM) while keeping impeller diameter constant:

Q₂/Q₁ = N₂/N₁
H₂/H₁ = (N₂/N₁)²
P₂/P₁ = (N₂/N₁)³

Where Q is flow rate, H is head, P is power, and N is speed.

Impeller Diameter Changes

When impeller diameter changes while keeping speed constant:

Q₂/Q₁ = D₂/D₁
H₂/H₁ = (D₂/D₁)²
P₂/P₁ = (D₂/D₁)³

Where Q is flow rate, H is head, P is power, and D is impeller diameter.

Additional Pump Engineering Resources

Pump Selection

Choose the right pump for your application

NPSH Calculation

Net Positive Suction Head analysis

System Curve Analysis

Analyze pump and system interactions

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