免费风管风速计算器
计算暖通风管中的气流速度。
CFM
in
Air Velocity
859 ft/min
Duct Area50.3 sq in
Noise Risk0
Air Velocity vs Airflow
公式
## Duct Air Velocity **V = CFM / A** Where A is the cross-sectional area of the duct in square feet. Convert the diameter from inches to feet before calculating the area. Residential duct velocity should stay below 700-900 ft/min to avoid noise.
计算示例
300 CFM through an 8-inch round duct.
- 01Area = pi x (8/24) squared = 0.349 sq ft
- 02Velocity = 300 / 0.349 = 860 ft/min
- 03This is borderline for noise; consider a 10-inch duct.
常见问题
What velocity causes noise?
Below 600 ft/min is quiet. 600-900 ft/min is acceptable. Above 900 ft/min produces noticeable noise. Supply registers should be under 500 ft/min.
How does velocity affect static pressure?
Higher velocity increases friction and pressure drop per foot of duct. This means the blower must work harder, reducing efficiency and increasing operating cost.
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