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Air chamber fill times

Air chamber fill times

Air chamber fill times

(OP)
I am looking for a simplified equation that I can use to estimate the time needed to fill a 1 cubic inch chamber from zero pressure to 100 PSI, using a solenoid valve with a Cv of .29, .9 or 1.4 and a supply of 120 PSI. Thanks

RE: Air chamber fill times

I imagine it is pretty quick

RE: Air chamber fill times

There is no simple equation. Up to ~60psi inside the chamber the flow into the chamber is a choked flow. However, when the pressure inside the chamber goes beyond ~60psi the flow into chamber is un-choked and it is influenced by the supply pressure and the pressure inside the chamber. There is also the influence of heat transfer through the walls of the chamber, therefore, it depends on the material of the chamber too. It can be solved only by numerical solving of the flow equations and thermodynamic of the gas combined with heat transfer equations.  

RE: Air chamber fill times

PVT(1) = PVT(2) a simple thermo equation that should get you pretty close.

RE: Air chamber fill times

IS IT AIR?

I'll assume air.
Cv = Q/(16.05 * SQRT((P1^2 - P2^2)/(SG * (T+460))))     
Where:

Cv = valve sizing coeffecient
Q = flow in SCFM
P1 = upstream pressure in PSI
P2 = downstream pressure in PSI
SG = Specific Gravity
T = temperature in degrees F

0.29 = Q/(16.05 * SQRT((135^2 - 15^2)/(1 * (60+460))))   

Neglecting all the stuff Israekk mentioned, isn't that like 1/100th of a second?  I'll let you work it if you need more accuracy than that

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso

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