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:

The head loss can be given in terms of a friction factor:

For laminar flow in a circular pipe,

There will be a head loss for the entrance:

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

Homework: 7.4

02/21/01 0:39:47 02/23/01 0:02:09