Pipe System - Flow Calcs - Tie Ins

[colar]

I am wondering if anyone has either a good reference (by good I mean more practical than theoretical) regarding calculating flow rates in new additions to existing pipe networks. Would also appreciate a couple of key thoughts or general attack steps in how something like this could be analyzed.

For example, if you worked in a large plant with a massive pipe network, how could you go about finding out what the potential flow rate would be if you tied into some point in that line and added a new branch? It would be very cumbersome to re-analyze the whole network. Is there a way to take some key characteristics (existing pressure and flow) at the location where you want to tie in and use these along with a calculated system curve to determine an operating point?

 

[BigInch]

You can do exactly that, if and only if you are absolutely sure that both the pressure at that point and the flow at that point can be maintained as you divert flow into the new lateral. In other words, the supply of fluid to that point must have enough capacity such that it can supply what it is flowing now plus whatever amount of flow you want to take off into the lateral, without reducing the pressure there now. With a relatively large increase in flow, its going to be difficult to maintain the same pressures in the supply pipe lines without increasing that supply's inlet pressure too. Then the increase head loss due to the higher flow will bring the pressure at the T back to where it is now. If you only take a relatively small amount into the lateral, you might be able to get away with it. Depending on your experience, you could be able to tell and decide if its a relativly large flow or not that you will take into the lateral. If you can't tell, then you will probably have to model the entire system to find out just what will happen as you divert flow into the T.

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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/

 

[MJCronin]

collar...

No, calculation of network flowrates is not all that cumbersome and having a developed computer model of a large multi-million dollar system is a reasonable thing to do.

We have junior engineers in our company performing exactly this task.

Computer software such as AFT Fathom takes the drudgery out of the calculations, IMHO

-MJC