1. What is a Constant Flow Rate Pump Calculator?

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

Purpose: It helps engineers and technicians determine the expected flow rate of a pump under specific operating conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

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

3. Importance of Flow Rate Calculation

Details: Accurate flow rate estimation ensures proper system design, pump selection, and energy efficiency in fluid transport systems.

4. Using the Calculator

Tips: Enter the 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: 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 60-85% efficiency (0.6-0.85), but this varies by pump type and size.

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

Q4: When would I change the fluid density?
A: Use different values when pumping fluids other than water (e.g., 6.6 lb/gal for gasoline, 10 lb/gal for brine).

Q5: Does this work for all pump types?
A: This formula is most accurate for centrifugal pumps operating at constant speed.