Backflow Pressure

[italzo]

Anyone have a good reference formula for calculating backflow pressure for a capsule like feature?...in other words, picture this: if you were to take a tylenol pill, cut it in half, and laser cut a quantity of 50 .004" diameter circles around the cylindrical face, how would one calculate the backflow pressure given a known flow rate?

Thanks!

 

[Latexman]

Sorry, I can't picture it in my mind. How about a sketch?

Good luck,
Latexman

 

[MintJulep]

You may find some leads in thread378-205170

 

[Artisi]

why not make one and flow test it.
The formula for orifice pressure drop is probably for holes thru a flat surface whereas you are talking about hole thru a cylindical surface meaning the holes are not of an area equal to 0.004" dia. if it were a flat surface. You could of course calculate the actual area and use it in any formula.

 

[GregLocock]

How accurate do you need to be?

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[italzo]

The application I have in mind is similar to a shower head - with many tiny holes in it: roughly .004" in diameter...so if there is a formula to calculate such backflow or back pressure, that would much be appreciated!...

Thanks!

 

[Latexman]

What is the L/D of these 0.004" holes? L would be the thickness of material the holes would have to penetrate. This will determine whether it is treated as an orifice or a small pipe or tube.

Good luck,
Latexman

 

[Artisi]

Did you refer to the posting from MintJulep - you need to have some input as well - not just ask questions.