Best Diameter of Pipe
Best Diameter of Pipe
(OP)
I am wondering what the best diameter of pipe is for a given volume flow rate. I understand that conductors are sized based on flow velocity, surface roughness etc. but I have read that fluid friction is reduced at the point of transition from laminar to turbulent...Is there a critical velocity for each given pipe size? Thanks in advance.





RE: Best Diameter of Pipe
RE: Best Diameter of Pipe
If you are looking for "rule of thumb" information as a starting point, consider 5-8 ft/s velocity as a first pass to start an itterative analysis of varying pipes sizes.
RE: Best Diameter of Pipe
Another article prepared by Barry Sloane titled " Economic Pipe Size - based on payback" has appeared in July 1994 issue of HP. The HP has a website.
a couple of article related to pipe sizing can also be found in chem. engineering web site. u may also wnat ot try pipingdesign.com.
RE: Best Diameter of Pipe
The chapter titles are as follows: 1. Fundamentals of optimum pipe size selection, 2. Least annual cost, 3. Selection according to pressure drop available, 4. Velocity allowable, 5. Two-phase flow, 6. Fluid mechanics parameters, 7. Preparations, 8. Pipe size selection for pump or compressor discharge, 9. Pipe size selection for pump or compressor suctions, 10. Pipe size selection for pressure drop allowable, 11. Steam piping for heating and reciprocating pumps, 12. Steam piping for turbines, 13. pressure let-down for gas, 14. Relief valve discharge headers, 15. Steam trap piping, 16. Two-phase flow applications, 17. Special velocity considerations, 18. Comparative capacities of pipes, 19. Mechods of approach, 20. Conclusion.
The book contains numerous examples of all types of piping applications, one to fit almost any circumstance. I highly recommend it!
RE: Best Diameter of Pipe
Also, liquid velocities are limited to 3 m/s but to 1.5 m/s for corrosive services.
The above are general guidelines and should be evaluated for the case considered.
For 2-phase flows, erosion velocity criterion needs to be checked (refer API 14E).
However, for 2-phase flow, nobody clearly mentions about phase velocities to be limited apart from erosion criteria. Logically, it should be checked. If anyone has something on this, let me know (especially kstaylor may have something in the book mentioned).
RE: Best Diameter of Pipe
Here's some good software to help you:
http://www.pressure-drop-calculator.com/ (freeware)
or, even better:
http://www.pipeflow.co.uk/ (30-day trial)
I would size the pipe for a liquid flow around 1.5 m/s
Good luck & Happy New Year!
RE: Best Diameter of Pipe
Regards
David Ribeiro
davidr@absamail.co.za
RE: Best Diameter of Pipe
I have a spreadsheet which calculates optimum economic pipe dia.Its not written by me though.If you are interested,give me your e-mail id. I will send it to you.
regards,
sdprocess
RE: Best Diameter of Pipe
Thank you very much, I think you have saved me a lot of time by your spreadsheet.
If I wanted to change the spreadsheet to suit my country's costs, does anyone have an idea on how to go about this? (South Africa)
Regards,
David Ribeiro
davidr@absamail.co.za
RE: Best Diameter of Pipe
If you are calculating life-cycle cost effectiveness, you have too much time on your hands.
RE: Best Diameter of Pipe
Time spent on life-cycle cost should be directly proportional to the scale of the project. If you are designing a 100' line, it does not justify the expense. However, if you are designing a 1000 mile pipeline, life-cycle cost are important and should be part of the design process.
RE: Best Diameter of Pipe
Much appreciated
David Ribeiro
davidr@absamail.co.za
RE: Best Diameter of Pipe
has been changed too:
www.carf-engineering.com
it is still freeware, please download the Economic Pipe Sizer under DOWNLOADS.
Hope this helps,
MVD
RE: Best Diameter of Pipe
Thanks for the web site!
David