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Velocity Formula:
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Duct velocity refers to the speed at which air flows through a duct in ventilation and air conditioning systems. It is a critical parameter in HVAC design that affects system performance, energy efficiency, and noise levels.
The calculator uses the fundamental fluid dynamics formula:
Where:
Explanation: This formula calculates the average velocity of air flowing through a duct based on the volume of air passing through per unit time and the cross-sectional area of the duct.
Details: Proper duct velocity is essential for efficient HVAC system operation. High velocities can cause excessive noise and pressure drops, while low velocities may lead to poor air distribution and potential sedimentation issues.
Tips: Enter flow rate in m³/s and area in m². Both values must be positive numbers. The calculator will compute the velocity in m/s.
Q1: What are typical duct velocity ranges for HVAC systems?
A: For main ducts: 5-10 m/s, branch ducts: 4-7 m/s, and terminal runs: 2-4 m/s, depending on the application and noise requirements.
Q2: How does duct velocity affect system performance?
A: Higher velocities increase friction losses and noise, while lower velocities may require larger ducts and can lead to air stratification and dust settlement.
Q3: Can I use this calculator for circular ducts?
A: Yes, but you must calculate the area using πr² where r is the radius of the duct in meters.
Q4: What units should I use for the inputs?
A: This calculator uses SI units: flow rate in cubic meters per second (m³/s) and area in square meters (m²).
Q5: How accurate is this calculation?
A: This provides the average velocity. Actual velocity may vary across the duct cross-section due to boundary layer effects and turbulence.