1. What is a Centrifugal Pump Sizing Calculator?

Definition: This calculator determines the flow rate (GPM) of a centrifugal pump based on horsepower, efficiency, total head, and fluid density.

Purpose: It helps engineers and technicians properly size centrifugal pumps for various fluid transfer applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute, GPM)
• \( HP \) — Horsepower input to the pump
• \( \eta \) — Pump efficiency (0-1, dimensionless)
• \( H \) — Total dynamic head (feet)
• \( \rho \) — Fluid density (pounds per gallon)

Explanation: The formula relates the mechanical power input to the hydraulic power output, accounting for pump efficiency and system requirements.

3. Importance of Proper Pump Sizing

Details: Correct pump sizing ensures efficient operation, prevents cavitation, matches system requirements, and reduces energy costs.

4. Using the Calculator

Tips: Enter the pump horsepower (HP), efficiency (default 0.8), total head in feet, and fluid density (default 8.34 lb/gal for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the constant 3960 in the formula?
A: This is a conversion factor that relates horsepower, flow rate, head, and specific gravity in consistent units.

Q2: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 50-85% efficiency (0.5-0.85), with 0.75-0.8 being common for well-designed pumps.

Q3: How do I determine total dynamic head?
A: Total head includes static head, friction losses, and pressure differences. It's calculated from your system design.

Q4: What density should I use for other fluids?
A: For other fluids, use their specific weight (lb/gal). For example, seawater is about 8.56 lb/gal, gasoline about 6.0 lb/gal.

Q5: Can this calculate required horsepower for a given flow?
A: Yes, the formula can be rearranged to solve for HP if you know the desired flow rate.