System Behavior

SYSTEM BEHAVIOR

The flow rate through a given piping system varies with the pressure drop or equivalent head loss. When the head loss is graphed versus flow rate, we have what is called a system curve.

Modified Bernoulli equation

Reynolds Number

Minor Losses

Is a term that refers to pressure losses encountered by a fluid as it flows through a fitting or a valve in a piping system

Example

The figure shows a piping system made of 3-nominal schedule 40 PVC pipe that conveys water from the tank. The level is variable, and so it is desired to have information on how the flow rate will vary through the system. It is proposed that the tank be replaced with a pump, and before such a decision is acted upon, a system curve must be drawn. Generate a system curve ∆H versus the Q for the setup shown assuming the tank liquid level z can vary from 0.3 to 2.5 m. The pipe length is 14m, and the distance from the pipe exit to tank bottom is 1.

Water=1000 =0.89x

3-nom sch 40ID=7.792cmA=47.69

PVC=“smooth”=0

(0.3)

L=14m

H=

V=

+14.8))

CREDITS

Arriesgado, Alfon Caesar V.

REFERENCEDesign of Fluid Thermal Systems, 3rd Edition

By William S. Janna