1. What is Centrifugal Pump Capacity?

Definition: This calculator determines the flow rate (capacity) of a centrifugal pump based on its power, efficiency, head, and fluid density.

Purpose: It helps engineers and technicians size pumps and evaluate their performance under different operating conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Pump capacity (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 pump's power input to its hydraulic output, accounting for efficiency and the work required to move the fluid.

3. Importance of Pump Capacity Calculation

Details: Proper pump sizing ensures efficient system operation, prevents cavitation, and matches pump performance to system requirements.

4. Using the Calculator

Tips: Enter the pump horsepower (HP), efficiency (default 0.85), 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, with larger pumps often at the higher end.

Q3: How do I determine total dynamic head?
A: Total head includes static head, friction losses, and pressure differences in the system.

Q4: What if I'm pumping a fluid other than water?
A: Adjust the density value accordingly (e.g., 6.6 lb/gal for gasoline, 9.3 lb/gal for seawater).

Q5: Does this account for NPSH requirements?
A: No, net positive suction head must be calculated separately to ensure proper pump operation.