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Old Mar 19th 2019, 05:17 AM   #1
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losses in air pipework

I have a 200m 3 /hr air blower at 0.344bar. assuming plastic pipe run is 2inch 100m straight. how can I work out losses from friction.
will the loss result in less air at the outlet or less pressure or both. Thanks for any help
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Old Mar 19th 2019, 06:30 AM   #2
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That works out at 55liters /sec ..........

50mm internal diameter ..... A = 19.6 cm 2 .........

55/ 1.96 = 29 m/sec that's the velocity of the air , not too fast , about 60MPH

So do you mean the blower delivers air at 200m3/hr against a pressure of 0.344bar?

The manufacturer of the blower should provide a graph of flow against back pressure ... a longer pipe will create more back pressure and reduce the flow rate...

Not easy to work out losses from friction in the pipe , different surfaces effect flow differently ... and pipe joints create turbulence (more back pressure).
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Last edited by oz93666; Mar 19th 2019 at 06:33 AM.
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Old Mar 19th 2019, 10:05 AM   #3
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Do you mean how do you work it out "theoretically" so that you can model it before you build it?

Or do you mean how do you work it out experimentally (after you have built it) so you can (perhaps) compare different builds?
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Old Mar 19th 2019, 03:35 PM   #4
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all I've been given is 200m3/hr @ 0.344 bar. I just want to know how to work out losses from the pipework. I know how to do for liquid but not sure on air. thx
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Old Mar 19th 2019, 05:14 PM   #5
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I can't see that there is enough information.

As I read the problem, your blower produces 200m^3/hr against a back pressure of 0.344 bar
(which I assume means 0.344 bar above atmospheric)

If friction in your pipe produces more back-pressure than this, you will expect to get less than 200m^3/hr.
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