Piping branch flow calculations
Piping branch flow calculations
(OP)
I am new to this, so bear with me, but can anyone direct me to a resource for line sizing calculations for branch flows? For example, if I have a piping configuration with water below
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-----------|----------->pump---->
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Can't seem to find any decent online material.
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-----------|----------->pump---->
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Can't seem to find any decent online material.
-Mike





RE: Piping branch flow calculations
RE: Piping branch flow calculations
RE: Piping branch flow calculations
Once you have specified the node pressures you calculate the segment line sizes. You would then have to select the nearest standard pipe size and recalculate the actual node pressures and see how this affects the other line size calculations. This is where some degree of iteration (trial and error) comes in.
If there are many branches you may have to make some simplifying assumptions, but these would be no different from the assumptions you would feed into the computer network model if you were going that route. I much prefer the "manual" method as a way of achieving a robust and meaningful solution. But then I am a grumpy old man.
If you have loops rather than branches, or if you do not have fixed flow rates, then the chances are that you are going to have to use the fancy software.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Piping branch flow calculations
I agree with katmar's assessment. Since the problem seemed so straightforward, my presumption was that there must be a more complex associated system that would be causing some concerns for you. In any case, you will have to make some idealizing assumptions to solve your problem.
RE: Piping branch flow calculations
Piping flow problems can easily become complex and require iterative solutions.
There are well-established software packages sold specifically for this purpose.
Consider this one:
http://www.aft.com/products/fathom/
When you use an established, recognized program, there is no doubt or concern about how you constructed a spreadsheet used to calculate a solution.
My opinion only
-MJc
RE: Piping branch flow calculations
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Piping branch flow calculations
My concern with the solutions from powerful software is always the old "garbage in = garbage out" problem. If the user is not able to do the simple problems by hand then asking them to use sophisticated software asking for trouble. I don't mean to insult the OP in any way, but it is important to learn to walk before you run.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Piping branch flow calculations
-Mike
RE: Piping branch flow calculations
RE: Piping branch flow calculations
I think you should describe your system more. What do you want to accomplish, are you in design phase or trying to guess some actual flows?
Example:
The picture above is return water from three oil coolers. The cooling water is gathered and pumped to a radiator field, then back to the different oil coolers.
Then we would:
1. Calculate the needed mass flow in each cooler/branch
2. Chose pipe size of branches to get a reasonable flow velocity
3. Calculate a pressure drop in the worst case branch
4. Insert throttle valves on the other lines in order to adjust the flow to the wanted
5. Calculate needed head of the pump
RE: Piping branch flow calculations
Also Haestad have been giving out free CDs at Expos with their book "Advanced Water Distribution Modelling and Management".
RE: Piping branch flow calculations
There's the problem...
there are 4 pumps in parallel.
pump1 is connected to boiler1 (1 1/4" pipe about 30' run)
pump2 is connected to boiler2 (1 1/2" pipe about 30' run)
pump3 and pump4 are connected to boiler3 (2 pumps for security. Only one works at a time)(1 1/2" pipe about 30' run)
Since pump1 is broken the client asks to connect all 4 pumps together in case one pump fails and he cant use one of his boiler. (Pumps wont always work at the same time, they have flow controllers)
I told him to connect his 4 pumps with a 1 1/2" pump (the largest pipe diameter), but a subcontractor tells me that a larger pipe diameter is required where the piping meets. Otherwise, the flow of 2 pumps will interfere.
Actually
B1 B2 B3
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P1 P2 P3 P4
Suggested
B1 B2 B3
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------------------------------------------
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P1 P2 P3 P4
Any tips why the contractor suggests larger pipe??
I thought that what comes in must go out... If the 1 1/2" was good enough for Pump3 or 4
RE: Piping branch flow calculations
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Piping branch flow calculations
Research the terms "flow distribution" and maldistribution.
How long would the common header have to be to tie all 4 pumps together?
Good luck,
Latexman
RE: Piping branch flow calculations
D = Rads[S*1,5/0.785]*10
D = header diameter (mm)
S = Total area of the pipe coming out the header (cm^2)
For your application the header should be 4"
RE: Piping branch flow calculations
D = SQRT[S*1,5/0.785]*10
D = header diameter (mm)
S = Total area of the pipe coming out the header (cm^2)
For your application the header should be 4"
RE: Piping branch flow calculations
RE: Piping branch flow calculations
Good luck,
Latexman
RE: Piping branch flow calculations
I have attached an example of how natural gas services are sized when branches are involved. You might use this as a guide in your problem.
RE: Piping branch flow calculations
-Mike
RE: Piping branch flow calculations
I worked with a guy (ex-Navy Chief) who changed that old GIGO to "Garbage in, Gospel out"
I always thought that was pretty funny and it actually describes the phenomenon more accurately...
RE: Piping branch flow calculations
Good luck,
Latexman
RE: Piping branch flow calculations
Patricia Lougheed
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