Flow Rate Calculator with Pressure

Flow Rate Formulas:

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

Initial Pressure (P₁):

psi

Final Pressure (P₂):

psi

Density (ρ):

lb/ft³

Cross-sectional Area (A):

ft²

Velocity (V): ft/s

Flow Rate (Q): GPM

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1. What is a Flow Rate Calculator with Pressure?

Definition: This calculator determines fluid flow rate (in GPM) through a pipe or channel using pressure difference, fluid density, and cross-sectional area.

Purpose: It helps engineers, plumbers, and fluid system designers calculate flow rates in piping systems based on pressure measurements.

2. How Does the Calculator Work?

The calculator uses two key formulas:

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

Where:

\( V \) — Fluid velocity (ft/s)
\( P_1 \) — Initial pressure (psi)
\( P_2 \) — Final 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, and the second converts velocity to flow rate in gallons per minute.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculations ensure proper system design, pump sizing, and verification of system performance in water supply, HVAC, and industrial processes.

4. Using the Calculator

Tips: Enter pressure values (psi), fluid density (default 62.4 lb/ft³ for water), and cross-sectional area (ft²). All values must be > 0 except P₂ which can be 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the 144 factor in the equation?
A: This converts psi to psf (pounds per square foot) since 1 psi = 144 psf.

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

Q3: What's a typical density value for water?
A: Fresh water at 60°F is 62.4 lb/ft³. Saltwater is about 64 lb/ft³.

Q4: How do I find the cross-sectional area?
A: For circular pipes: \( A = \pi \times (D/2)^2 \) where D is diameter in feet.

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