Physics Help Forum losses in air pipework

 Thermodynamics and Fluid Mechanics Thermodynamics and Fluid Mechanics Physics Help Forum

 Mar 19th 2019, 05:17 AM #1 Junior Member   Join Date: Dec 2018 Posts: 7 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
 Mar 19th 2019, 06:30 AM #2 Senior Member   Join Date: Apr 2017 Posts: 484 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). topsquark likes this. Last edited by oz93666; Mar 19th 2019 at 06:33 AM.
 Mar 19th 2019, 10:05 AM #3 Senior Member     Join Date: Jun 2016 Location: England Posts: 880 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? __________________ ~\o/~
 Mar 19th 2019, 03:35 PM #4 Junior Member   Join Date: Dec 2018 Posts: 7 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
 Mar 19th 2019, 05:14 PM #5 Senior Member     Join Date: Jun 2016 Location: England Posts: 880 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. __________________ ~\o/~

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