Flow Rate Calculator Using Pressure

Flow Rate Formulas:

\[ V = \sqrt{\frac{2 \times (P_1 - P_2) \times 144}{\rho}} \] \[ Q = V \times A \times 448.83 \]

Inlet Pressure (P₁):

psi

Outlet Pressure (P₂):

psi

Fluid Density (ρ):

lb/ft³

Pipe Area (A):

ft²

Velocity (V): ft/s

Flow Rate (Q): GPM

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1. What is a Flow Rate Calculator Using Pressure?

Definition: This calculator estimates fluid flow rate (in GPM) through a pipe based on pressure difference, fluid density, and pipe cross-sectional area.

Purpose: It helps engineers, plumbers, and fluid system designers determine flow rates in piping systems.

2. How Does the Calculator Work?

The calculator uses two formulas:

\[ V = \sqrt{\frac{2 \times (P_1 - P_2) \times 144}{\rho}} \] \[ Q = V \times A \times 448.83 \]

Where:

\( V \) — Fluid velocity (feet per second)
\( P_1 \) — Inlet pressure (psi)
\( P_2 \) — Outlet pressure (psi)
\( \rho \) — Fluid density (pounds per cubic foot)
\( Q \) — Flow rate (gallons per minute)
\( A \) — Pipe cross-sectional area (square feet)

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

3. Importance of Flow Rate Calculation

Details: Accurate flow rate estimation ensures proper system design, pump sizing, and meets process requirements in industrial, plumbing, and HVAC systems.

4. Using the Calculator

Tips: Enter pressure values (P₁ > P₂), fluid density (default 62.4 lb/ft³ for water), and pipe area. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: Why is there a 144 in the formula?
A: This converts psi (lb/in²) to lb/ft² (1 ft² = 144 in²).

Q2: What's the 448.83 conversion factor?
A: This converts ft³/s to GPM (1 ft³/s = 448.83 GPM).

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

Q4: How do I calculate pipe area?
A: For circular pipes: \( A = \pi \times (diameter/2)^2 \), with diameter in feet.

Q5: Does this account for friction losses?
A: No, this is ideal flow. For real systems, consider additional pressure drop from pipe friction.