免费暖通风管选型计算器
根据风量和风速选择合适的风管尺寸。
Required Circular Duct Diameter
252 mm
Required Circular Duct Diameter vs Airflow Rate (Q)
公式
HVAC Duct Sizing
Duct size is determined by the airflow requirement and an acceptable air velocity.
Formula
A = Q / V (required area)
D = sqrt(4Q / (pi V)) (circular duct diameter)
where Q is airflow in m^3/s and V is maximum velocity in m/s. Higher velocity means smaller ducts but more noise and pressure drop.
计算示例
300 L/s airflow with 6 m/s maximum velocity.
- 01Q = 300 L/s = 0.30 m^3/s
- 02A = 0.30 / 6 = 0.05 m^2 = 50,000 mm^2
- 03D = sqrt(4 x 0.30 / (pi x 6)) x 1000 = sqrt(0.0637) x 1000 = 252 mm
- 04Round up to next standard size: 250 or 300 mm duct.
常见问题
What air velocity is recommended for ducts?
Main supply ducts: 5-8 m/s. Branch ducts: 3-5 m/s. Near grilles/diffusers: 2-3 m/s. Return air: 3-5 m/s. Higher velocities save on duct size but increase noise and fan power.
What are standard round duct sizes?
Common diameters: 100, 125, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800 mm. Select the next standard size up from the calculated diameter.
How do I convert to rectangular duct?
For an equivalent rectangular duct, keep the same cross-sectional area. For a rectangular duct a x b with the same friction as a circular duct D, use the hydraulic diameter formula: D_eq = 1.3 (ab)^0.625 / (a+b)^0.25.
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