1. What is Pump Efficiency?

Pump efficiency (η) is the ratio of hydraulic power delivered to the fluid to the mechanical power input at the pump shaft. It indicates how effectively the pump converts mechanical energy into fluid flow energy.

2. How Does the Calculator Work?

The calculator uses the pump efficiency equation:

Where:

• \( \eta \) — Pump efficiency (unitless, 0 to 1)
• \( \rho \) — Fluid density (kg/m³)
• \( g \) — Gravitational acceleration (9.81 m/s²)
• \( Q \) — Volumetric flow rate (m³/s)
• \( H \) — Total dynamic head (m)
• \( P_s \) — Shaft power (W)

Explanation: The equation calculates the ratio of hydraulic power output (ρgQH) to mechanical power input (P_s).

3. Importance of Pump Efficiency

Details: Pump efficiency is crucial for energy conservation, operational cost reduction, and proper pump selection. Centrifugal pumps typically have efficiency curves that vary with flow rate.

4. Using the Calculator

Tips: Enter all values in consistent SI units. Density for water is approximately 1000 kg/m³. Efficiency values range from 0 (worst) to 1 (best, 100% efficient).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical efficiency range for centrifugal pumps?
A: Typically 40-85%, with higher efficiency for larger pumps operating near their best efficiency point (BEP).

Q2: Why does efficiency vary with flow rate?
A: Pumps have an optimal operating point (BEP) where losses (friction, recirculation, etc.) are minimized.

Q3: How can I improve pump efficiency?
A: Operate near BEP, use proper impeller size, maintain pumps regularly, and consider variable speed drives.

Q4: What affects pump efficiency?
A: Pump design, size, speed, viscosity, specific gravity, system head curve, and operating point.

Q5: What's the difference between hydraulic and overall efficiency?
A: This calculator gives hydraulic efficiency. Overall efficiency includes mechanical losses in bearings/seals.