Minor loss in air ducts based on a summarized minor loss coefficients and air flow velocity:
- 1 Pa = 1 N/m2 = 1.4504x10-4 lb/in2 = 1x10-5 bar = 4.03x10-3 in water = 0.336x10-3 ft water = 0.1024 mm water = 0.295x10-3 in mercury = 7.55x10-3 mm mercury = 0.1024 kg/m2 = 0.993x10-5 atm
Minor loss for some common duct-work components like bends, expansions, inlets and outlets can be estimated from the diagrams below.
Minor Loss Coefficients - Bends
The minor loss coefficients in 90o bends can be estimated with the diagram below.
The minor loss in bends 0 - 180o can be estimated with the equation
ξ0-180 = ξ90 α / 90 (1)
ξ0-180 = minor loss coefficient for the bend with the actual angle
ξ90 = minor loss coefficient for the 90o bend according the diagram above
α = angle of the actual bend
The minor loss coefficient in a 90o bend like the one below is 1.0.
Minor Loss Coefficients - Expansions
Minor Loss Coefficients - Inlets
Minor Loss Coefficients - Outlets
Systems for ventilation and air handling - air change rates, ducts and pressure drops, charts and diagrams and more.
Minor loss (pressure or head loss) coefficients for air duct components.
Typical air duct velocities in applications like ventilation systems or compressed air systems.
A major friction loss diagram for air ducts - SI units.
Calculate pressure loss - or head loss - in ducts, pipes or tubes.
Minor pressure and head loss in pipes vs. equivalent length in tubes and duct systems.
Minor loss coefficients for components used in pipe and tube systems.
Velocity diagram for rectangular air ducts - metric units.
Minor pressure or head loss in ventilation ducts vs. air velocity - minor loss coefficient diagram.