HEAD LOSS

Fluid Flow HEAD LOSS HEAD LOSS The head loss that occurs in pipes is dependent on the flow velocity, pipe length and diameter, and a friction factor based on the roughness of the pipe and the Reynolds number of the flow. The head loss that occurs in the components of a flow path can be correlated to a piping length that would cause an equivalent head loss. EO 1.21 DEFINE the terms head loss, frictional loss, and minor losses. EO 1.22 DETERMINE friction factors for various flow situations using the Moody chart. EO 1.23 CALCULATE the head loss in a fluid system due to frictional losses using Darcy’s equation. EO 1.24 CALCULATE the equivalent length of pipe that would cause the same head loss as the minor losses that occur in individual components. Head Loss Head loss is a measure of the reduction in the total head (sum of elevation head, velocity head and pressure head) of the fluid as it moves through a fluid system. Head loss is unavoidable in real fluids. It is present because of: the friction between the fluid and the walls of the pipe; the friction between adjacent fluid particles as they move relative to one another; and the turbulence caused whenever the flow is redirected or affected in any way by such components as piping entrances and exits, pumps, valves, flow reducers, and fittings. Frictional loss is that part of the total head loss that occurs as the fluid flows through straight pipes. The head loss for fluid flow is directly proportional to the length of pipe, the square of the fluid velocity, and a term accounting for fluid friction called the friction factor. The head loss is inversely proportional to the diameter of the pipe. Head Loss µ f^Lv 2 D Friction Factor The friction factor has been determined to depend on the Reynolds number for the flow and the degree of roughness of the pipe’s inner surface. Rev. 0 Page 31 HT-03