Trying to convert differential pressure (inch WC) measurements from a 6-inch diameter pipe into an air flow rate (cfm).(adsbygoogle = window.adsbygoogle || []).push({});

Here's what I got so far...

I'm assuming laminar, imcompressible flow with negligible friction, head, or thermal losses (this is a very low-flow system). From the Bernoulli equation...

V = (2P/d)^0.5

V = velocity

P = differential pressure

d = air density @ STP

area = A = pi(r^2)

flowrate = Q = VA

Seems straightforward enough, but when I plug in my pressure readings, I'm getting too high of a result for Q (I get a result I'd expect for a fan, and not the dribbling of air I'm actually getting from the pipe).

I think I have the units converted correctly, so am I missing something in the velocity equation?

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# Homework Help: Converting pressure to flow rate

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