Dont know how to word this properly, but a question on volume, flow, and psi.

[SwGts]

I don't know if this is the right section, and I am not entirely sure on how to word this- Hoepfully I can make this clear enough however:

If we know the volume of a setup, for a simple example let's just say a small straight tube. If we know the psi inside this tube, is it possible to calculate the CFM going through the tube to get that psi? Is it possible to Keep the same volume tube, retain the same Psi, and increase the cfm?

Hope I've made this clear enough.

 

[mgb_phys]

If you know the pressure DROP along a tube (or across an opening) and you know the density and viscosity of the fluid you can get the (approximate) flow rate.
It's slightly different equation depending on the speed etc.

http://en.wikipedia.org/wiki/Orifice_plate