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Air Flow Rate Equation:
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The air flow rate equation (Q = A × v) calculates the volumetric flow rate of air through a duct based on the cross-sectional area and air velocity. This fundamental equation is widely used in HVAC system design and ventilation engineering.
The calculator uses the air flow rate equation:
Where:
Explanation: The equation calculates the volume of air passing through a duct per unit time by multiplying the duct's cross-sectional area by the air velocity.
Details: Accurate air flow rate calculation is essential for proper HVAC system design, ensuring adequate ventilation, maintaining indoor air quality, and optimizing energy efficiency in building systems.
Tips: Enter cross-sectional area in square meters (m²) and air velocity in meters per second (m/s). Both values must be positive numbers greater than zero for accurate calculation.
Q1: What units should I use for the calculation?
A: The calculator uses metric units (m² for area, m/s for velocity, m³/s for flow rate). For imperial units, convert to metric first or use appropriate conversion factors.
Q2: How do I measure duct cross-sectional area?
A: For rectangular ducts, multiply width by height. For circular ducts, use π × (diameter/2)². Ensure consistent units throughout.
Q3: What is a typical air velocity in HVAC ducts?
A: Typical velocities range from 2-5 m/s for low-velocity systems and 5-10 m/s for high-velocity systems, depending on application and noise considerations.
Q4: Can I use this for liquid flow calculations?
A: Yes, the same equation applies to incompressible fluids, but ensure proper units and consider fluid properties for precise engineering applications.
Q5: How does duct shape affect the calculation?
A: The equation uses cross-sectional area regardless of shape, but actual flow characteristics may vary due to friction losses and flow distribution differences.