air start motor attached to pressure vessel
air start motor attached to pressure vessel
(OP)
I am working with a system that starts with a tank of pressurized air, goes through some piping, a pressure reg valve, some more piping, a solenoid valve and then a turbine style air start motor. I am trying to analyze the system for a 20 second run time (the tank is pressurized to some standard, a solenoid is opened at t=0 and the valve stays open for 20 sec.) I need to know the pressure and flow at the turbine and also volume of air left in the tank after the 20 seconds. Since each component has its own restrictions on volumetric flow what would be a good method to do this? Also, since the head loss of the components is based on the flow rate, how do I include that in the calculation since it keeps changing? Feels like some sort of differential equation, but I'm not sure how to begin.





RE: air start motor attached to pressure vessel
The starter has a consumption rate in CFM, so CFM times minutes is how much air you will have to remove from the tank. Typically the starter is rated in SCFM so assume that calculation reveals that you nee 500 CFM at 90 psig. If the tanks holds 1000 SCF at 200 psi it holds about 500 SCF at 100, so the tank can supply the 500 SCF at a pressure ABOVE the 90 psig the starter needs. Your regulator must be able to pass the listed flowrate with a 10 psi DP. Finished.
RE: air start motor attached to pressure vessel
I'm sorry I did not mention these before, I guess I oversimplified.
RE: air start motor attached to pressure vessel
If the pressure at the ASMs is fluxuating, then the system is undersized. Even in this cast teh ASM should only see two possible pressures. The pressure with one running or the pressure with two running. So you only have two flow states to address.
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