Saturday, December 6, 2008

Pressure Drop

When using a sharp edged orifice the pressure drop across any hole size can be determined using the following formula.

FLOW1/SQ RT DELTA PSI1 = FLOW2/SQ RT DELTA PSI2.

This assumes that FLOW1 and DELTA PSI1 are known and the hole size remains the same.

2 comments:

Anonymous said...

That applies not only a sharp edge orifice, it applies to any orifice as a general equation where k=Q/sqrt deltaP. You are assuming/estimating that constant k is the same all throughout downstream. If two flow controls are in series, I guess k will vary at every orifice point.

JDK said...

Not sure what you are talking about. This equation is true for a knife edged orifice. The flow across the orifice must be "turbulent" not "laminar".

Your statement "You are assuming/estimating that constant k is the same all throughout downstream." makes no sense to me.