|
[Sponsors] |
June 29, 2004, 17:08 |
Gas flow through a 90 deg Elbow
|
#1 |
Guest
Posts: n/a
|
I am a mechanical engineer, who does flow calculations occasionally. I have been asked to estimate the loss of pressure of a gas flowing through a 90 deg. elbow. Is there any ready formala for doing this, and is there any references somebody can help me. Thanks a lot for your assistance.
|
|
June 29, 2004, 20:59 |
Re: Gas flow through a 90 deg Elbow
|
#2 |
Guest
Posts: n/a
|
The Diffrence Between pressure inlet and pressure outlet will be total pressure loss.
|
|
June 29, 2004, 22:12 |
Re: Gas flow through a 90 deg Elbow
|
#3 |
Guest
Posts: n/a
|
My problem is I only know the inlet pressure, and may not have an oppurtunity to plug a pressure gauge after the outlet. I have to predict the pressure loss before the equipment is built. Any input is greatly appreciated.
|
|
June 30, 2004, 08:36 |
Re: Gas flow through a 90 deg Elbow
|
#4 |
Guest
Posts: n/a
|
Hi yes you can use an approximate loss coefficient approach.
The pressure head loss (h) can be approximated as... h = (k*u*u)/(2g) as h = dp/(rho*g) you can re-arrange to get dp = k. 0.5*rho*u*u I assume you know or can calculate the density and average flow velocity. The value of k can be found listed in tables for differend bends/valve/etc. a 90 degree elbow has a k coefficient of 0.9 i.e. loss of pressure = 0.9 * dynamic pressure dp = 0.9 * 0.5* density * velocity squared This is described fully in the book 'mechanics of fluids' by B.S. Massey . ISBN 0-412-34280-4 alternatively you can calculate the friction factor from a moody chart and use a l/d approximation to find the pressure loss hf = f . (l/d) (vel squared/2g) Darcy weisbach equation try http://www.engineering.uiowa.edu/~fl...Chapter_10.pdf Good luck Tim, |
|
June 30, 2004, 11:43 |
Re: Gas flow through a 90 deg Elbow
|
#5 |
Guest
Posts: n/a
|
Tim,
Thanks a lot, appreciate your help. |
|
July 4, 2004, 09:29 |
Re: Gas flow through a 90 deg Elbow
|
#6 |
Guest
Posts: n/a
|
Have a look in:
Fluid Flow - Internal Flow Systems 2nd Edition by D.S. Miller This has pretty much everything you need to know about doing pipe flow calculations. Regards James |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
real gas simulation in ejector for supersonic flow | rahul_bhad1 | FLUENT | 1 | March 31, 2015 22:12 |
Appropriate model for turbulent, steady state pipe elbow flow | milos | OpenFOAM Running, Solving & CFD | 4 | July 9, 2009 03:24 |
Plug Flow | Franck | Main CFD Forum | 3 | September 4, 2003 06:57 |
ideal gas law in turbulent flow | Achim | Siemens | 0 | March 26, 2003 15:38 |
flow in gas turbine | Abdul Hafid | Main CFD Forum | 1 | September 14, 1998 10:39 |