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Line Sizing
3

Line Sizing

Line Sizing

(OP)
Can anyone advice me what are the steps requires for Line Sizing?
I have not done this earlier.

Thanks,
Chem55

RE: Line Sizing

Learn the theory and application of the Darcy-Weisbach equation by obtaining and studying Crane Technical Paper #410 and Cameron Hydraulic Data.  Both can be obtained through the internet.

The above will familiarize you with the basic division existing between compressible and non-compressible flow.  And this only applies to Newtonian fluids.  For 2-phase flow, you've a lot of more studying and reading to do but I assume you are not going to go that far into the subject.

Work the various example problems illustrated in Crane's Tech Paper #410 and that should be enough to get you up and started on sizing simple hydraulic circuits.

RE: Line Sizing

3
As a start do the following:

1- check the flow region either Turbulent or Laminar
Re= (de.*vel.* Dia / vis.)
Turbulent Re > 2000
Laminar Re < 2000
constants usually given Q, de. ,vis.
Guess Dia
vel. = Q/A where A= pi/4 Dia^2

2- A) use Fanning's equation for Re> 2000
delta P = (4*f)(L/Dia)(de.* vel.^2/2)*10^-5
B) use Hagen-Poisuille's eqaution for Re <2000:
delta p = (32)(vis.* vel.*L/Dia^2)10^-5
where L is pipe length (straight)
Note all units are in SI

3- Calculate delt P resulting from fittings i.e. elbows..etc using isometric drawing
4- Find the total pressure drop of the system that is
delt P of the straight length + delt P of the fittings

5- If the resulting pressure drop matches your system pressure drop requirement then, the guess Dia is the line Diameter

6- If step 5 is not correct try another Dia to satisfy your required pressure drop

7- Other criteria if not pressure drop is of a concern, i.e, there is no anchor point in the system, you might be limited with velocity requirements, if so, follow steps 1 to 4 and check the velocity result

I hope this would help you in understanding the piping hydraulic calculations since this is what the eng. offices are doing for designing a plant but via their own software for the whole plant with many integrated piping,
what you can do is to develop a spreadsheet with steps I mentioned and you will benefit a lot

Regards



RE: Line Sizing

Apart from Arts input i woul also recomend that you check your companys engineering manual. Most companies where lines shall be sized deals with this issue - and also contains special requirements or experience

Best regards

Morten

RE: Line Sizing

Try to keep Reynolds numbers out of ranges between 2000 to 3000.  The friction factor in that flow regime is extremely hard to prerdict.

RE: Line Sizing

Get yourself a copy of Crane Technical Paper No. 410. All of the information is contained therein.

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