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Originally Posted by swabbie58
True, I am just having trouble comparing apples to oranges. For example, the 59.4CF of air coming in starts life at 14psi and is forced into the 6.6CF tank. The force pushing it along will be sufficient to do this job. The air in the tank is constantly increasing in pressure under this influx or decreasing as some is exhausted. I need a formula to figure out how this tank pressure will be simultaneously influenced by both of these processes.
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I think you are reading more into your problem more than you need to. You could easily install a pressure switch to turn off your compressor at a specified setpoint.
At any rate, you want the mass flow at the inlet and exit to be the same. Mass flow is a function of density, velocity and the area at the inlet / exit.
Continuity equation:
rho1V1A1 = rho2V2A2
rho1 = density at inlet
V1 = velocity at inlet
A1 = area at inlet
rho2 = pressure at exit
V2 = velocity at exit
A2 = area at exit
Also, you probably want the ideal gas law to convert for density:
PV = NRT
P = pressure
V = volume
N = moles
R = gas constant - 8.314 (kpa*m^3)/(kmol*K)
T = temperature
There are a few websites that can explain the theory. Try
www.engineeringtoolbox.com. If I were you I would worry more about the mechanical energy needed to maintain your assumed constant flow at high pressure.
-Jake