1. What is Flow Rate from Pressure Difference?

Definition: This calculator determines the flow rate (in gallons per minute) through a pipe or channel based on the pressure difference between two points.

Purpose: It helps engineers and technicians in fluid systems to estimate flow rates when pressure measurements are available.

2. How Does the Calculator Work?

The calculator uses two formulas:

Where:

• \( V \) — Velocity (ft/s)
• \( P_1 \) — Upstream pressure (psi)
• \( P_2 \) — Downstream pressure (psi)
• \( \rho \) — Fluid density (lb/ft³)
• \( Q \) — Flow rate (GPM)
• \( A \) — Cross-sectional area (ft²)

Explanation: The first equation calculates velocity from pressure difference, the second converts velocity to flow rate.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate estimation is crucial for system design, pump sizing, and process control in fluid systems.

4. Using the Calculator

Tips: Enter both pressures (P₁ > P₂), fluid density (default 62.4 lb/ft³ for water), and cross-sectional area. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What's the 144 factor in the equation?
A: This converts psi (lb/in²) to lb/ft² (1 ft² = 144 in²).

Q2: Why 448.83 in the flow rate formula?
A: This converts ft³/s to GPM (1 ft³/s = 448.83 GPM).

Q3: What's a typical fluid density for water?
A: Pure water at 60°F is 62.4 lb/ft³. Density changes with temperature and impurities.

Q4: Can I use this for gases?
A: No, this formula is for incompressible fluids. Gases require different calculations.

Q5: How do I measure cross-sectional area?
A: For circular pipes: \( A = \pi \times (diameter/2)^2 \).