Velocity and Volume Flow Rate Formula

Flow Rate Formula:

\[ Q = V \times A \times 448.83 \]

Flow Rate (Q):

GPM

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Velocity and Volume Flow Rate Formula?

Definition: This calculator determines the volumetric flow rate (Q) in gallons per minute (GPM) based on fluid velocity (V) and cross-sectional area (A).

Purpose: It helps engineers, plumbers, and fluid system designers calculate flow rates in pipes and channels.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q = V \times A \times 448.83 \]

Where:

\( Q \) — Volumetric flow rate (gallons per minute)
\( V \) — Fluid velocity (feet per second)
\( A \) — Cross-sectional area (square feet)
448.83 — Conversion factor (ft³/s to GPM)

Explanation: The formula converts the basic flow rate (velocity × area) from cubic feet per second to gallons per minute.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculations are essential for proper system design, pump selection, and ensuring adequate fluid delivery.

4. Using the Calculator

Tips: Enter the fluid velocity in ft/s and the cross-sectional area in ft². Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why 448.83 as the conversion factor?
A: It converts ft³/s to GPM (1 ft³/s = 448.83 GPM).

Q2: How do I find the cross-sectional area?
A: For circular pipes: \( A = \pi \times r² \) where r is radius in feet.

Q3: What's a typical velocity for water in pipes?
A: 2-5 ft/s for residential plumbing, up to 10 ft/s for industrial applications.

Q4: Can I use this for other fluids?
A: Yes, but the velocity ranges may differ based on fluid viscosity.

Q5: How does pipe diameter affect flow rate?
A: Flow rate increases with the square of the pipe diameter (double diameter = 4× flow rate at same velocity).