Flow through multiple orifices

[Pinfloc]

Hello,
I'm trying to solve a problem for balancing flow through multiple orifices on a common header. There are 3 oifices on 90 degree laterals in series on a header, two on tees and the last on an elbow, and they must be sized to distribute flow equally. I know the orifice equation, but I'm unsure how to solve for the various sizes of three. I am given Q in MGD, pipe diameter, distance between header laterals and lateral length. Flow is submerged with 5 feet of head on the discharge side. Got any hints?
Thank you.

 

[bimr]

Size the orifices so that you get 10-15 psi headloss across each orifice. Size the headers so that the piping loss is minimal in the headers.

 

[GoldDredger]

Sounds like a student's homework problem.

 

[escrowe]

Sounds like my swimming pool filtration effluent manifold.
I just fiddle with the valves until the discharge looks even.
Got a heater, too. :]

 

[gerhardl]

Sorry, my programs do not support your shared file format, but:

If the openings are really latheral (at the same level) and the output value of each is of a size where the flow can be considered laminar without turbulence, the common header could be regarded as a vessel with equalized (balanced) inside pressure. The pressure outside (5 feet of water) would also be equal.

In this case equal size of openings will give equal flow.

If you start to vary one of the first factors, you will have to vary one or several openings, each influencing inside pressure and flow also for the other openings.

Start with equal openings and see if this will give a good enough result. If not you either have to redesign the header, enlarging pipes/header going for more laminar flow and less inside loss, to give equal openings.

The other alternative is to start fiddeling....