1. Centrifugal Pump Power Formula

The pump power formula calculates the required power to move a fluid through a system. It accounts for fluid properties, flow requirements, and system efficiency.

2. Understanding the Variables

The formula components are:

Where:

• \( P \) — Power required (Watts)
• \( \rho \) — Fluid density (kg/m³, water ≈1000)
• \( g \) — Gravitational acceleration (9.81 m/s²)
• \( Q \) — Volumetric flow rate (m³/s)
• \( H \) — Total dynamic head (meters)
• \( \eta \) — Pump efficiency (0 to 1, typically 0.6-0.8)

Explanation: The formula calculates the hydraulic power needed to move the fluid, then divides by pump efficiency to get actual power requirement.

3. Practical Applications

Details: This calculation is essential for selecting appropriately sized pumps, motors, and power supplies in water systems, HVAC, industrial processes, and irrigation systems.

4. Using the Calculator

Tips:

• For water systems, density is typically 1000 kg/m³
• Convert flow rates from L/s to m³/s by dividing by 1000
• Total head includes static lift and friction losses
• Typical pump efficiencies range from 60-80% (0.6-0.8)

5. Frequently Asked Questions (FAQ)

Q1: How do I account for viscous fluids?
A: For viscous fluids, use the actual density and consider that efficiency may be lower than with water.

Q2: What's a typical efficiency value?
A: Centrifugal pumps typically range from 60-80% efficiency, with larger pumps often more efficient.

Q3: How does head relate to pressure?
A: Head (in meters) can be converted to pressure (in kPa) by multiplying by fluid density and gravity (P = ρgh).

Q4: Should I add a safety factor?
A: Yes, it's common to add 10-20% to the calculated power for safety margins and future needs.

Q5: How does this relate to motor sizing?
A: The calculated power is the hydraulic power. Motor power should be higher to account for mechanical losses.