Minor Loss Coefficients for Air Duct Components
Minor loss - pressure or head loss - coefficients for air duct distribution systems components
Sponsored Links
Minor Loss - Head or Pressure Loss in Air Duct Components - can be expressed as
hminor_loss = ξ v2/ 2 g (1)
where
hminor_loss = minor head loss (m, ft)
v = flow velocity (m/s, ft/s)
g = acceleration of gravity (m/s2, ft/s2)
Minor loss can also be expressed as pressure loss instead of head loss.
Minor loss coefficients for different components common in air duct distribution systems
| Component or Fitting | Minor Loss Coefficient - ξ - |
| 90o bend, sharp | 1.3 |
| 90o bend, with vanes | 0.7 |
| 90o bend, rounded radius/diameter duct <1 |
0.5 |
| 90o bend, rounded radius/diameter duct >1 |
0.25 |
| 45o bend, sharp | 0.5 |
| 45o bend, rounded radius/diameter duct <1 |
0.2 |
| 45o bend, rounded radius/diameter duct >1 |
0.05 |
| T, flow to branch (applied to velocity in branch) |
0.3 |
| Exit to room | 1.0 |
| Entry from room | 0.5 |
| Reduction, tapered | 0 |
| Enlargement, abrupt (due to speed before reduction) (v1= velocity before enlargement and v2 = velocity after enlargement) |
(1 - v2 / v1)2 |
| Enlargement, tapered angle < 8o (due to speed before reduction) (v1= velocity before enlargement and v2 = velocity after enlargement) |
0.15 (1 - v2 / v1)2 |
| Enlargement, tapered angle > 8o (due to speed before reduction) (v1= velocity before enlargement and v2 = velocity after enlargement) |
(1 - v2 / v1)2 |
| Grilles, 0.7 ratio free area to total surface | 3 |
| Grilles, 0.6 ratio free area to total surface | 4 |
| Grilles, 0.5 ratio free area to total surface | 6 |
| Grilles, 0.4 ratio free area to total surface | 10 |
| Grilles, 0.3 ratio free area to total surface | 20 |
| Grilles, 0.2 ratio free area to total surface | 50 |
Sponsored Links
Sponsored Links
Engineering ToolBox - SketchUp Edition - Online 3D modeling!
Engineering ToolBox - SketchUp Edition - enabled for use with the amazing, fun and free Google SketchUp.
Search the ToolBox
© The Engineering ToolBox 2005
9 6 19
