Orifice flow calculation.

[FXguy]

I'm looking for a orifice and pipe flow calculation to determine a certain lbs/hr or CFM through that orifice with given pressures.

 

[Cockroach]

American Gas Association, Report Number 3. This is identical to American Petroleum Institute Report 14.3.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[MortenA]

Now this post will propa give a lot of different answres. I once tried to collect some of the typical in a FAQ:

http://www.eng-tips.com/faqs.cfm?fid=841

- however if want to be more precise try to tell us:

- Is it a liquid or a gas
- Is it for measurement or restriction

Best regards

Morten

 

[stanier]

The MAthcad Collaboratory had a posting providing a calculation to meet BS 1042 requirements.

Crane Technical Paper 410 Flow of Fluids provides all the necessary data. You can buy over the net.

 

[FXguy]

Sorry folks this was ment for GAS. I'm looking for a orifice and pipe flow calculation to determine a certain lbs/hr or CFM through that orifice with given pressures.

Also thanks for the great response.

 

[mbeychok]

.
FXguy:

For gas flow through orifices (in SI metric units) see:

http://www.air-dispersion.com/msource.html

For gas flow through orifices (in U.S.A. customary units) see:

http://www.air-dispersion.com/usource.html

Milton Beychok
(Contact me at www.air-dispersion.com)
.

 

[stanier]

Try some of the instrument companies. They may have calculation software available. If not on the Net their sales guys may have it in the office. Try Daniel, Invensys etc. Do a google on differential transmitters and flowmeters and see who pops out.

Crane does also cover comressible flow

Try any instrument book by Spinks

 

[swainw]

Pressure drop across the orifice is significant to your problem. If the flow is choked as in the gas has reached sonic in the throat area the flow rate can be determined from gas dynamics tables. But you will need to know some entrance values such as T to determine the rho, density. This sets your m.dot for the flow rate., m.dot = rho*. A * V (velocity)

Once thats known your throat conditions can be determined and hence your pressure drop across the device from further calcs. In practice its easier to instrument the upstream or down stream conditions as the flowing temp of the gas to set conditions to determine rho is often difficult.

Good luck,
Bill

Bill Swain
Ultra Electronics Precison Air Systems
Technical Coordination Manager-US Programs
swainw@asme.org