Pump Shaft Power Calculator Formula

Pump Shaft Power Formula:

\[ SP = \frac{Q \times H \times \rho \times g}{\eta} \]

Flow Rate (Q):

m³/s

Head (H):

Density (ρ):

kg/m³

Efficiency (η):

decimal

Shaft Power (SP):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Pump Shaft Power Formula?

The Pump Shaft Power formula calculates the mechanical power required at the pump shaft to move a fluid. It considers flow rate, head, fluid density, and pump efficiency to determine the actual power input needed.

2. How Does the Calculator Work?

The calculator uses the Pump Shaft Power formula:

\[ SP = \frac{Q \times H \times \rho \times g}{\eta} \]

Where:

\( SP \) — Shaft Power (kW)
\( Q \) — Flow rate (m³/s)
\( H \) — Head (m)
\( \rho \) — Fluid density (kg/m³)
\( g \) — Gravitational acceleration (9.81 m/s²)
\( \eta \) — Pump efficiency (decimal)

Explanation: The formula calculates the power required to move a specific volume of fluid against a certain head, accounting for the pump's efficiency.

3. Importance of Shaft Power Calculation

Details: Accurate shaft power calculation is essential for proper pump selection, motor sizing, energy consumption estimation, and system design optimization.

4. Using the Calculator

Tips: Enter flow rate in m³/s, head in meters, fluid density in kg/m³, and pump efficiency as a decimal (0-1). All values must be positive with efficiency between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between shaft power and hydraulic power?
A: Hydraulic power is the theoretical power required to move the fluid, while shaft power includes the pump's efficiency and represents the actual power input at the pump shaft.

Q2: How does fluid density affect shaft power?
A: Higher density fluids require more power to pump since more mass is being moved against the same head.

Q3: What is typical pump efficiency range?
A: Pump efficiency typically ranges from 0.5 to 0.9 (50-90%), depending on pump type, size, and operating conditions.

Q4: Why is gravitational acceleration included?
A: Gravitational acceleration (g) is needed to convert the head (in meters) to the pressure energy required to lift the fluid.

Q5: Can this formula be used for all pump types?
A: This formula is generally applicable for centrifugal and positive displacement pumps, though specific pump characteristics may require additional considerations.