Volumetric Air Flow Rate Formula

Volumetric Flow Rate Formula:

\[ Q = A \times v \]

Volumetric Flow Rate (Q):

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1. What is Volumetric Air Flow Rate?

Volumetric air flow rate (Q) represents the volume of air passing through a given cross-sectional area per unit time. It is a fundamental parameter in fluid dynamics, HVAC systems, ventilation design, and various engineering applications.

2. How Does the Calculator Work?

The calculator uses the volumetric flow rate formula:

\[ Q = A \times v \]

Where:

\( Q \) — Volumetric flow rate (m³/s)
\( A \) — Cross-sectional area (m²)
\( v \) — Velocity of air flow (m/s)

Explanation: The formula calculates the volume of air flowing through a duct, pipe, or opening by multiplying the cross-sectional area by the average velocity of the air stream.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation is essential for designing ventilation systems, determining air exchange rates, sizing ductwork, calculating pressure drops, and ensuring proper air quality in buildings and industrial processes.

4. Using the Calculator

Tips: Enter cross-sectional area in square meters (m²) and velocity in meters per second (m/s). Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between volumetric and mass flow rate?
A: Volumetric flow rate measures volume per time (m³/s), while mass flow rate measures mass per time (kg/s). They are related by density: mass flow rate = volumetric flow rate × density.

Q2: How do I measure cross-sectional area for irregular shapes?
A: For irregular ducts, calculate the equivalent diameter or use integration methods. For circular ducts, area = π × (diameter/2)².

Q3: What are typical air velocities in ventilation systems?
A: Typical velocities range from 2-5 m/s in main ducts, 1-3 m/s in branch ducts, and 0.5-1.5 m/s in diffusers, depending on application and noise requirements.

Q4: How does temperature affect volumetric flow rate?
A: Temperature affects air density but not the volumetric flow rate directly. However, mass flow rate changes with temperature due to density variations.

Q5: When is this formula not applicable?
A: The formula assumes uniform velocity profile and incompressible flow. For compressible flows at high velocities or with significant pressure changes, more complex equations are needed.