A member of a physics list using the speed of a CO2 extinguisher propelled cart found the exit speed of the CO2 to be ~ the speed of sound. He thinks this is too great. I think his value may possibly be ~ correct. I suggested another method to check the value, quoting:
Perhaps not too "big". Another approximate method is to assume all the energy (not a good assumption?) of compression is converted to the KE of the mass of CO2. This would supply an internal consistency cheque.
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I'm too lazy to think thru the thermodynamics or lit. search for this thermodynamical process, and don't have his data to do the calc.
Are any of you not so lazy and, therefore, will advise us?
bc remembers under those conditions CO2 is not an ideal gas and work will be done "against" the Van der Waals force, and some solid CO2 may result. Also it's mildly throttled, not free.