Pressure drop through perforated pipe inlet
Pressure drop through perforated pipe inlet
(OP)
I am pulling water out of a 500 psi pressure vessel with a 12" perforated pipe. I need to calculate the pressure drop across the perforated holes. Essentially, it is a sparge tube flowing in the reverse direction. Would a sparge tube pressure drop calculation still be accurate with the reverse flow?





RE: Pressure drop through perforated pipe inlet
At 500 psi I'm struggling to work out why you need to know to any level of accuracy.
How many holes?
Total area of holes compared to area of pipe?
Flow velocity at end of pipe?
Pressure in pipe?
Multi hole pipes are not simple and depends on a lot of factors
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pressure drop through perforated pipe inlet
All the pressure drops are important because the system we are using to generate the pressure represents a significant portion of the cost of the unit. Also, the flow through perforations occurs along multiple points in the system, so it is possible for the pressure drop to become significant.
RE: Pressure drop through perforated pipe inlet
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
RE: Pressure drop through perforated pipe inlet
There are multiple vessels in series and the system uses the same perforation pattern and flow rate for various inlet and outlet points along the line. Hope that clarifies a little.
RE: Pressure drop through perforated pipe inlet
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
RE: Pressure drop through perforated pipe inlet
IMO, the pressure drop for each hole on the perforated pipe may be depended on the water flow pattern inside the vessel and the location of the hole on the pipe. If the flow pattern can't be changed, you may want to increase the hole number or size to reduce the pressure drop.
RE: Pressure drop through perforated pipe inlet
Calculated Cv for the array is 1223.64 gpm/sqrt(psid).
Velocity in each hole is 3.49 mph.
That assumes all holes are at the same elevation, in a 'thin' sheet, and are punched or drilled 'clean', with no burrs, no chamfer, and no radius.
Machinists and fabricators often round off hole edges so they will 'flow better', but that makes the calculations impossible/erroneous because edge effects are hugely sensitive to the actual edge conditions. Better to avoid any mention of fluid metering on the shop drawings.
Mike Halloran
Pembroke Pines, FL, USA
RE: Pressure drop through perforated pipe inlet
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
RE: Pressure drop through perforated pipe inlet
I was considering doing each hole from an orifice approach as well.
Thank you all for your time, input, and expertise.
RE: Pressure drop through perforated pipe inlet
If this is a dead end pipe then the flow will be constantly changing and the pressure loss across each hole very small, but different for each set of holes as you go down the pipe from the end to the ooen end.
I don't get the series of vessels bit
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pressure drop through perforated pipe inlet
a) in the chapter on fluid transport
b) in the chapter on gas liquid contacting systems - this may for sparger systems only if I remember correctly (forward flow).
McGraw Hill and / or the section editor have ripped out the former in the 7th edition.