1. What is Flow Rate in a Pump?

Definition: This calculator determines the flow rate (in gallons per minute) that a pump can deliver based on its horsepower, efficiency, 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)
• \( HP \) — Horsepower
• \( \eta \) — Pump efficiency (0 to 1)
• \( H \) — Total dynamic head (feet)
• \( \rho \) — Fluid density (pounds per gallon)

Explanation: The formula relates the pump's power input to the hydraulic work done, accounting for the pump's efficiency 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 optimization.

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: It's 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 85% being common for well-designed pumps.

Q3: How do I determine total dynamic head?
A: It's the sum of static head, friction losses, and pressure head in the system.

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

Q5: Does this formula work for all pump types?
A: It's most accurate for centrifugal pumps. Positive displacement pumps require different calculations.