Pipe networks

[landrover77]

ladies / gents

I have a closed pipe system in which i have two separate pipe loops each with their own pump. Loop1, Loop2
The two loops interact by two branches which feed from Loop 1 into Loop 2 and vice versa. The flow required through branch 1 = flow through branch 2. I have attached a diagram to illustrate.

i know the pipework loss factors for all pipe, and the flow rate i require around both cicuits and through each branch.

but How do i calculate actually how much water will flow through the branch and how much will continue through the loop? clearly this will be pressure drop related?
note in practice i can vary valve Pd to create the required pressure drop to allow the correct flow.

many thanks in advance.

 

[vpl]

Do you have a copy of Crane's Technical Paper 410, "Flow of Fluids?"

Patricia Lougheed

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[landrover77]

no sorry i don't - i will look to download a copy, but how should i approach this?

 

[landrover77]

i've have purchased a copy, but i can't any of the examples that relate to what i'm trying to do. I wondered can someone point me in the right direction please.

 

[SNORGY]

creed12:

Start at the node(s) where the flow splits. It appears that you have target flows in mind for each branch. Set your flow rates per branch accordingly and calculate the pressure losses between the flow split and the respective delivery (or return) point. The branch with the lowest calculated dP requires more throttling in order for the flow to balance as assumed.

Have you (or has anyone) considered buying Crane's TP-410-based software (link below):

http://www.flowoffluids.com/

I haven't downloaded the demo myself or worked with it. The price is $1195.00 U.S.; if the software is a fraction as good as the hardcopy TP-410, it's probably money well woth spending.

It looks like it can probably deal with situations exactly like this one.

Regards,

SNORGY.

 

[vpl]

Snorgy

The software is well worth it, IMHO. However, it's usually beyond the pocket of an individual (though cheap for his company.) The book on the other hand is cheap enough that even a new engineer can afford it.

Creed12

You've got a diagram so presumably you know the real (or proposed) layout for the piping -- pipe sizes, # of bends, # and types of valves, etc.

Remember "conservation of flow." The total amount of water in the system can't increase or decrease (because we're presuming no leaks!) Label each section with an identifer to keep them straight. Then do as Snorgy said, using the information in the Crane book (smart purchase!)

It will be iterative to get everything to where you want it. If this is something where you will have to adjust things frequently, then after you've done all the calculations once, it would probably be a good idea to suggest to your management that buying the software is a good investment.

Patricia Lougheed

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[SNORGY]

vpl:

Do you have, or have you purchased, the software? I value your opinion. I am very strongly considering springing for it personally. I am also pretty sure that if I use it myself and can show its value to management here, they would probably buy a copy for the company *plus* reimburse me for my own.

Well...the engineering managers would...

Maybe not the MBAs...

Not that I am in any way bitter...

Regards,

SNORGY.

 

[vpl]

I don't have the software -- I'm no longer on the engineering side of my company, and can't justify buying it. I have a coworker who has it and highly recommends it (Crane used to give out a copy if you took their course.) The price has gotten more expensive over the years, but is still cheaper than a lot of other similar softwares.

Patricia Lougheed

******

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[SNORGY]

Please tell me you didn't become an MBA...

Regards,

SNORGY.

 

[BigInch]

You might want to play around with EPANET.
Its totally free.

"We have a leadership style that is too directive and doesn't listen sufficiently well. The top of the organisation doesn't listen sufficiently to what the bottom is saying." Tony Hayward CEO BP
"Being GREEN isn't easy." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.liv