Colebrook Equation 1

[steve1]

I'm looking for information regarding when to use the Colebrook Equation for gas distribution piping. The Weymouth and Panhandle formulas are geared primarily for long pipeline lengths. The Colebrook equation is primarily used for distributation. Any referance data will be appreciated.

 

[ghaz]

the gas engineers handbook or the pipeline rule of thumb manual have reference information.
NFPA 54 has recommended sizes for various lengths for housepiping.
Formulas typically are used more for pressure class than lengths.

 

[Smith]

For short pipelines and gathering systems I use Weymouth formula. It works properly and the friction factor is function of the diameter. This allows me not to look for iterative solutions.

If you use Colebrok you need a graph with the friction factor, you can find in Section 17 of the Engineering Data Book of the Gas Processors Association.

Good luck

 

Steve

If you use the general flow equation with the Colebrook friction factor method you can't go wrong. The Method follows the Moody diagram to a tee (Except for the transitional flow region – which, in the gas distribution world, hardly comes into play). The tricky part is to solve for f, which is on both sides of the Colebrook equation. You will have to iterate. You can do this on a spreadsheet or even a good calculator.

Most of the other gas equations are very valid. IGT, Mueller, AGA, etc… are very valid. However – they do not follow the lines on the moody diagram like Colebrook.

I have written an excel spreadsheet, access VB, and math cad calculators that will do this. I can email them to you if you would like. Also – You can download a trial version of Gas Calc from the Bradley Bean Co.

Also – Go to

http://www/psig.org

there are some excellent papers on this subject.