The main points of this chapter are summarized below.
Head Loss Summary
Head loss is the reduction in the total head (sum of potential head, velocity head,
and pressure head) of a fluid caused by the friction present in the fluids motion.
Frictional loss is that part of the total head loss that occurs as the fluid flows
through straight pipes.
Minor losses are the head losses that occur due to bends, elbows, joints, valves,
and other components. Any time the flow experiences a change in direction or
a change in cross-sectional area, it will experience a head loss.
The friction factor for fluid flow can be determined using a Moody Chart if the
relative roughness of the pipe and the Reynolds number of the flow can be
Darcys equation can be used to calculate frictional losses.
A special form of Darcys equation can be used to calculate minor losses.
The length of pipe that would cause the same head loss as a valve or fitting can
be determined by multiplying the value of L/D for the component found in
handbooks or vendor manuals by the diameter of the pipe.