Flow Rate Calculator 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 a Flow Rate Calculator from Pressure and Diameter?

Definition: This calculator estimates fluid flow rate (in GPM) through a pipe based on pressure difference and pipe diameter.

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

2. How Does the Calculator Work?

The calculator uses these 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)
\( P_1 \) — Upstream pressure (psi)
\( P_2 \) — Downstream pressure (psi)
\( \rho \) — Fluid density (lb/ft³, default 62.4 for water)
\( Q \) — Flow rate (GPM)
\( A \) — Cross-sectional area of pipe (ft²)

Explanation: The pressure difference drives the flow, with velocity determined by the Bernoulli principle, and flow rate calculated from velocity and pipe area.

3. Importance of Flow Rate Calculation

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

4. Using the Calculator

Tips: Enter the pressure difference (P₁ - P₂), 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: Why is the pressure multiplied by 144?
A: This converts psi to psf (pounds per square foot) since density is in lb/ft³ (1 ft² = 144 in²).

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

Q3: When would I change the fluid density?
A: For fluids other than water (e.g., oil at ~55 lb/ft³, seawater at ~64 lb/ft³).

Q4: Does this account for friction losses?
A: No, this is ideal flow. For long pipes, consider additional calculations for friction losses.

Q5: What's the typical velocity range for water in pipes?
A: Generally 4-8 ft/s for supply lines, 2-5 ft/s for drainage.