Subject:- Refrigeration and Air Conditioning

Topic:- Duct Design and Applications

Difficulty:- Low

The pressure is lost due to friction between the moving particles of the fluid and the interior surfaces of a duct. This is termed as friction loss.

$p_f=\frac{(fLρ_a V^2)}{2m} where m=\frac{(cross sectional area (A))}{(wetted perimeter (P))}$

Pressure is also lost dynamically at the changes of direction such as in bends, …