air flow rate control

[bwilson6561]

In an application I'm designing, air is vented from a portable air tank. In order to decrease the frequency of refills, it is desired to carry as much air in the tank as possible. This means the tank pressure will be around 80 to 100 psi above atmosphere.

But the application only requires a small flow rate of a certain value, say, at most 0.05 standard cubic feet per minute (scfm).

Does varying the "orifice size" or the diameter of the air passage control the air flow for a given pressure?

What is the equation for this? Thanks

 

[BigInch]

Its the pressure difference across the orifice that determines the flow through it. See this page here,

http://www.mcnallyinstitute.com/13-html/13-12.htm

http://virtualpipeline.spaces.msn.com

 

[BigInch]

and this online calculator here,

http://www.efunda.com/formulae/fluids/calc_orifice_flowmeter.cfm#calc

http://virtualpipeline.spaces.msn.com

 

[Ashereng]

Yes. For a given inlet pressure, if you make the hole smaller, you will reduce flow (because by making the hole smaller, the differential pressure across the hole gets bigger).

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[25362]

Is the upstream pressure also variable ?
Read thread124-139392.