Flow Rate from Pressure and Diameter

Flow Rate Formulas:

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

Upstream Pressure (P₁):

psi

Downstream Pressure (P₂):

psi

Fluid Density (ρ):

lb/ft³

Pipe Diameter:

inches

Velocity (V): ft/s

Flow Rate (Q): GPM

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1. What is Flow Rate from Pressure and Diameter?

Definition: This calculator estimates the flow rate (in gallons per minute) through a pipe based on pressure difference and pipe diameter.

Purpose: It helps engineers and technicians determine fluid flow rates in piping systems for design and analysis purposes.

2. How Does the Calculator Work?

The calculator uses two main formulas:

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

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 of pipe (ft²)

Explanation: The first formula 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 is crucial for proper system design, pump selection, and ensuring adequate fluid delivery in piping systems.

4. Using the Calculator

Tips: Enter the upstream and downstream pressures in psi, fluid density (default 62.4 lb/ft³ for water), and pipe diameter in inches. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What does the 144 factor represent?
A: It converts psi (lb/in²) to lb/ft² (since 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?
A: Water at 60°F is 62.4 lb/ft³. For other fluids, use their specific density.

Q4: Does this account for friction losses?
A: No, this is an ideal calculation. For real systems, consider additional losses.

Q5: What pipe shapes does this work for?
A: The calculator assumes circular pipes. For other shapes, use equivalent diameter.