Values

Typical head loss values for important situations may be found in tables. For bends and area changes, they can be expressed as a head loss coefficient: .

Exercise:

Why express the headloss in terms of ? Why not, say, ?

For the developed two-dimensional duct flow in the previous subsection, the head loss over a distance L of the duct is:

This head loss (called major head loss) can be given in terms of a friction factor:

For laminar flow in a circular pipe,

There will be an additional head loss for the entrance effects (called minor head loss):

For the duct exit, the kinetic energy will probably be mostly lost:

You should now be able to do 7.3 and 4