1. What is Pump Flow Rate?

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

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

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The formula relates the pump's power input to its fluid output, accounting for system resistance and fluid properties.

3. Importance of Flow Rate Calculation

Details: Proper flow rate estimation ensures adequate system performance, prevents pump overload, and helps in energy efficiency calculations.

4. Using the Calculator

Tips: Enter pump horsepower, 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, and head (1 HP = 3960 GPM·ft·lb/gal).

Q2: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 0.5-0.9, with 0.7-0.8 being common for many applications.

Q3: How do I determine total head?
A: Total head is the sum of static head, friction head, and pressure head in the system.

Q4: What density should I use for other fluids?
A: For other fluids, use their specific weight divided by 7.48 (gallons per cubic foot).

Q5: Can this be used for all pump types?
A: This formula is most accurate for centrifugal pumps. Positive displacement pumps require different calculations.