Calculating Air Flow Through a Pipe

Air Flow Rate Formula:

\[ Q = A \times v \]

Flow Rate (m³/s):

1. What is Air Flow Through a Pipe?

Definition: This calculator determines the volumetric flow rate of air moving through a pipe based on its cross-sectional area and velocity.

Purpose: It helps HVAC engineers, industrial designers, and ventilation specialists calculate air movement in duct systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q = A \times v \]

Where:

\( Q \) — Volumetric flow rate (cubic meters per second, m³/s)
\( A \) — Cross-sectional area of the pipe (square meters, m²)
\( v \) — Air velocity (meters per second, m/s)

Explanation: The flow rate is simply the product of the pipe's internal area and the average air velocity through it.

3. Importance of Air Flow Calculation

Details: Proper airflow calculation ensures efficient ventilation, proper system sizing, and energy optimization in HVAC systems.

4. Using the Calculator

Tips: Enter the pipe's cross-sectional area in m² (for circular pipes: π × radius²) and the measured air velocity in m/s.

5. Frequently Asked Questions (FAQ)

Q1: How do I calculate area for a circular pipe?
A: Use \( A = \pi r^2 \) where r is the radius in meters. For diameter (D), use \( A = \pi (D/2)^2 \).

Q2: What's a typical air velocity in ducts?
A: For HVAC systems, typically 2.5-7.6 m/s (500-1500 ft/min) depending on application and noise considerations.

Q3: How does temperature affect the calculation?
A: This calculator gives volumetric flow. For mass flow, you'd need to account for air density which changes with temperature.

Q4: Can I use this for liquids?
A: Yes, the same formula applies to incompressible fluids like water, but not for compressible flow with significant pressure changes.

Q5: How accurate is this calculation?
A: It assumes uniform velocity profile. Real systems may need corrections for turbulence, pipe roughness, and velocity distribution.