How do you calculate head loss?

Answer 1

Head loss can be found by manipulating the Bernoulli equation as follows:

Ideal fluid: [P1/ρg] + Z1 + [V12/2g] = [P2/ρg] + Z2 + [V22/2g] (assuming no energy loss)

Where P = pressure at the point

ρ = density of the fluid at all points in the fluid.

Z = elevation of the point above some reference plane (i.e. distance from top and/or bottom

surface of the filter media to the bottom reference plane in this case)

V = fluid flow speed at a point on a streamline

Non-ideal fluid: [P1/ρg] + Z1 + [V12/2g] = [P2/ρg] + Z2 + [V22/2g] + H

(Where H = Head loss or energy head)

∴ H = [(P1-P2)/ρg] + (Z1-Z2) + [(V12-V22)/2g]