Orifice plate design
Orifice plate design
(OP)
Hello to all
I am new to Fluid Mechanics, I a currently trying to divide a flow into two pipes with diffrent pressure drop each, The problem I am facing is that the flow must be equally divided, so as a solution I am thinking about using an orifice plate, yet these "instrument" are generally used to mesure pressure drop, my question is as follows:
Is it possible to use an orifice plate to control the flow rate into 2 pipes?
looking forward to recieving your replies
I am new to Fluid Mechanics, I a currently trying to divide a flow into two pipes with diffrent pressure drop each, The problem I am facing is that the flow must be equally divided, so as a solution I am thinking about using an orifice plate, yet these "instrument" are generally used to mesure pressure drop, my question is as follows:
Is it possible to use an orifice plate to control the flow rate into 2 pipes?
looking forward to recieving your replies





RE: Orifice plate design
Perhaps you can explain what you are trying to accomplish and the tolerance in flow spilt that you would like to achieve.
RE: Orifice plate design
Things like the length of the pipes, the relative pressures etc will make a difference.
Fluid will always want to flow down the easiest flow path so what you are actually trying to do by the sounds of it is actualy make the two systems have the same pressure drop.
Yes, orifice plates can do this, but they are fixed, so any small change in overall flow rate, density, temperature, viscosity etc will mean it will quickly go out of balance.
Can orifice plates be used to "control" the flow rate - Basically no unless everything else is fixed and doesn't change.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Orifice plate design
I wil try to give you a discription of the piping layout and the overall system:
It is a fire fighting piping layout, so I have fire pumps pumping fire water into a venturi proportionner, the output fluid of the latter is foam concentrate, at the end I have 4 foam makers with the same carateristics (flow = 2000 L/min........working pressure = 5 barG), a part from the orifice plate, is there any other solution to equilibate flow in general, and specefically in my case (existing fire pumps and an already built site which restrains creating pressure drop usin regular methods such as pipe length and fittings).
Looking forward to recieving your replies
RE: Orifice plate design
Still not easy to understand your layout. A sketch would help.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Orifice plate design
On the other hand a simple orifice, even if it does not give exactly the required flow, may be more reliable than an automatic valve that has sat unused for months or a manual valve that may have been tampered with. It depends on how rigorous your maintenance and testing program is.
Katmar Software - AioFlo Pipe Hydraulics
http://katmarsoftware.com
"An undefined problem has an infinite number of solutions"
RE: Orifice plate design
Hope this could help, Another question came across my mind while elaborating this simulation:
Could there be somekind of logigramme or a step-by-step method to minimize the number of iterations to be conducted in order to get the right flow in each pipe ?
I believe that someone must have thought of it !!
looking forward to receiving your replies
RE: Orifice plate design
Though I've not worked on fire fighting water supply networks before, would imagine a 5-10% variation in supply flow between J17 and J19 would be tolerable. So size the pipes such that this dp variation limit at max total flow is met? Adding an RO at J17 may also help if the line length from the supply tee to J17 to the supply for J19 is very long.
RE: Orifice plate design
From J8 then work out the total pressure drop to each element. e.g. flow from J8 to J 10 is 50% of total.
Pressure are J10 is the same for both branches, but flow is 25% of total.
Do this for all branches.
Work out which one has the highest pressure drop then start to work backwards and then you will be able to see where you need to artificial pressure drop via your orifice plates.
e.g. from J 13 to J 19 (the highest pressure drop), your pressure drop is, say, 10 psi, but from J 13 to J 18 it is only 5. You know the flow, you know the pipe size, so then you can calculate an orifice size to add 5 psi to the J 13 to J 18 leg.
Do the same for the two main branches.
If only three are on then it won't work.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Orifice plate design
RE: Orifice plate design
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Orifice plate design
BIG THANKS TO ALL