Pressurization Rate Orifice Calculation

[sailordude]

Hello, I am trying to calculate a orifice diameter that will keep my pressure change below a certain value. I basically have a 12" x 12" x 12' steel box that requires hole/s so that it may vent below a certain rate during altitude changes. I have looked at various threads but can't seem to find what I need/ understand.

Thx

 

[sailoday28]

will this help?

thread391-101311

 

[sailordude]

Hi Sailoday28, there is some good discussion but I realy don't know what direction to take. The example you provided is exactly what I am dealing with. Any other ideas?

 

[sailordude]

Any one else have a take on this?

Thx

 

[Cockroach]

SailorDude, you need to look at the advanced mathematical models at the American Gas Association, like AGA 14.3 specification or something equivalent, API. Without the proper additional pipe size and pressure drop information, I can't even guess.

You can approximate the hole size for incompressable flows using the Bernoulli Equation, but working fluid must be "well behaved" and less than 10% of the Mach Number. You can use the thermal tables, as I like to, but this is not a common practice.

There are websites that offer a service. Ever try to Google on "Orifice Computations"?

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada