Parallel Pipe
Parallel Pipe
(OP)
Any excel sheets out there to calculate flow through parallel pipes? As in, giving the flowrate in, the pipe sizes, lengths, and C values, what are the flow rates through the 2 seperate pipes?
I know there are formulas out there, just wondering if it's already prepackaged into a free excel spreadsheet...
I know there are formulas out there, just wondering if it's already prepackaged into a free excel spreadsheet...





RE: Parallel Pipe
http://www
Matt
RE: Parallel Pipe
RE: Parallel Pipe
http://virtualpipeline.spaces.msn.com
RE: Parallel Pipe
http://virtualpipeline.spaces.msn.com
RE: Parallel Pipe
Avoid Hazen Williams especially for large pipelines. Use Darcy Wiesbach
Geoffrey D Stone FIMechE C.Eng;FIEust CP Eng
www.waterhammer.bigblog.com.au
RE: Parallel Pipe
I noticed that some of Friend’s curves of velocity vs. friction loss per example length of pipeline in his paper now near 40 years ago (some comparing Hazen-Williams, Manning, Scobey, and Darcy, though even more approaches are talked about in his paper) laid quite nearly right on top of each other in a couple different pipe size examples he provided with sizes up to 24", particularly in 2-7 fps/1-2 m/s water flow ranges that I believe are quite common even to this day in water systems (it is thus quite possible most or all of these referenced engineers or scientists/technologists may have been quite competent, at least for their day!) Of course there are thousands of projects and maybe in aggregate hundreds of thousands miles/kilometers of pipelines designed with up to 24" sizes.
I guess I would only add that in my opinion the latter part of Mr. Friend’s quote above may be true of all equations – if you put good information into the left side of a sensible equation you can get good results on the right side, if you enter garbage on the left side you may well get garbage on the right!
RE: Parallel Pipe
http://virtualpipeline.spaces.msn.com
RE: Parallel Pipe
Whilst I respect your opinion and the work our forebears have performed there is evidnece out there that for large pipelines Darcy Weisbach is a more accurate approach. This is especially so if the fluid is not water.
Yes the horse and cart did transprot goods. But now we have semi trailers. No need to look back.
Many engineers use Hazen Williams as it is easy to write a spreadsheet algorithm than the recursive requirement of Darcy Weisbach. Just laziness really.
It seems civil engineers use HW and mechanical and chemical engineers DW formulas. perhaps the problem lies at the university professor's door.
Geoffrey D Stone FIMechE C.Eng;FIEust CP Eng
www.waterhammer.bigblog.com.au
RE: Parallel Pipe
http://www.pipefitter.com/PipingCalcMan.html
http://virtualpipeline.spaces.msn.com
RE: Parallel Pipe
As far as application to very large size pipes, I suspect pipe size in general, and certainly any available laboratory work were generally some smaller in Hazen-Williams day as a result of populations served (we cannot blame them for this!) Arguably few things in any field stay exactly the same forever, and I believe there has in fact even been some evolution in recent decades of the HW approach, it would appear perhaps even anticipated by folks nearly as far back as Friend (see the last part of the quote I provided earlier). In this regard, I also noticed in a new book published by Haestad/Bentley, “Advanced Water Distribution Modeling and Management that there now are some at least slight adjustments advocated e.g. in the values suggested for friction coefficient C as the pipe sizes get very large – see “C-factor” table at http
As far as blaming “university professors” for the use of HW, I wouldn’t do that either. While I haven’t been sitting in a university classroom for awhile, I suspect many competent professors are at least exposing students to multiple methods, and I wouldn’t be surprised if they in general are even spending a great deal more time trying to teach inarguably more complex DW than they are HW, because as you’ve noted anyone who can look at readily available tables or correctly type/chain one formula into an Excel program, or who can input a few numbers/punch buttons on a scientific calculator (in the right sequence for the power functions to work, and in the right units etc.), can in effect thus use HW!
RE: Parallel Pipe
DW was taught as the gold standard,
there was a mild discussion of H-W in the text but the units were intentionally left out to prevent the students from using such an easy equation,
DW has a broader scope allowing different fluids, viscosity's and densities, but if you are using water at normal distribution temperatures, not many fittings, with flows exceeding laminar but not excessive velocities, use the simple solution, this then allows the expansion of the simple solution to the complex environment of a water distribution system with great accuracy, because any well built model will be calibrated to adjust the C value to the results of pressure measurements and flow tests
Hydrae