Change in Pipe Section
Pressure head loss due to change in pipe size or shape
Contents
Overview
The sudden changes or the introduction of bends or valves disturbs the flow pattern along the pipe. The result is an increase in turbulence and this increases the frictional losses.Drop in momentum
Sudden Contraction

The head lost is given by: k is a constant and in this case is approximately 0.5. The value of
Head Loss At An Obstruction (e.g. A Valve)
The general equation for the head loss due to an obstruction, including bends, elbows, gate values, etc, is- k is the constant associated with the obstruction
- v is velocity
Fitting or Obstruction | Value for K |
---|---|
Standard 45 degree Elbow | 0.5 |
Standard 90 degree Elbow | 1.0 |
Globe Value - fully open | 10.0 |
Gate Valve - fully open | 0.2 |
Proof

Last Modified: 31 Dec 11 @ 14:58 Page Rendered: 2022-03-14 17:33:43