1. What is the Centrifugal Pump Flow Rate Formula?

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

Purpose: It helps engineers and technicians size pumps and evaluate their performance in fluid systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The formula relates pump power to flow rate by accounting for the energy required to move fluid against gravity and friction.

3. Importance of Pump Flow Rate Calculation

Details: Accurate flow rate calculation ensures proper system design, prevents pump overload, and optimizes energy consumption.

4. Using the Calculator

Tips: Enter pump horsepower, 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: It's the conversion factor that relates horsepower, flow rate, head, and specific gravity (1 HP = 3960 GPM·ft·SG).

Q2: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 50-85% efficiency, with 70-80% being common for well-designed pumps.

Q3: How do I determine total dynamic head?
A: Total head is the sum of static head (vertical distance) and friction head (pipe losses). Specialized calculations are needed for complex systems.

Q4: Why does fluid density matter?
A: Denser fluids require more energy to pump, resulting in lower flow rates for the same power input.

Q5: Can this formula be used for other pump types?
A: This is specific to centrifugal pumps. Positive displacement pumps use different calculations.