Pipe flow over an orifice - pressurised system

[noland1]

Hi

We are trying to determine a design method for distributing water over an area evenly through a pressurised system using 32mm dia pipes with orifices at 0.3m along the length of the pipe. We would be looking to discharge approximately 500 litres intermittently each time. My difficulty is im not sure how my approach should be to designing a successful method. i.e is it pipe flow across a series of orifices that i design for, or is it simply related to the internal volumes of the pipe and the pressure of the pump?

Our design requires us to have pipes laid parallel at 0.6m centres. Could anyone be able to help me or put me in the right direction of what calculations i should be doing.I have attached a rough sketch of a drawing i came across. If ayone could help me come up with a method to design something like this i would really appreciate it because i would like to be able to stand by a design rather than using generic designs. I think the feeder pipe shown would have to be a larger diameter for a start?

Bewildered young engineer

[admin]

You can experiment with orifice calculator at:
http://www.pipeflowcalculations.com/orifice/

There you can enter D1 - internal pipe diameter D2 - orifice diameter and p2 - outside pressure which is 101325 Pa if water goes to atmosphere.
You should also know flow though single orifice as total flow / number of holes - q1.
Than with different p1 values you will get different q - flow rate values through orifice (p1 - is pressure in front in orifice)
When you get q1 - equal to q in calculator, than you have p1.
That pressure you must have in 32 mm pipes.

Keep the velocity in feed pipe around 1 m/s. To calculate diameter of that pipe use diameter calculator at:
http://www.pipeflowcalculations.com/flowrate/ with known total flow rate and 1 m/s velocity.

This is to lead you in right direction.

[noland1]

Thanks, I'll get cracking on that so!!