Page 1 of 1

combustion pressure ?

Posted: Thu Nov 30, 2006 4:09 pm
by kris
has anyone ever recorded the peak pressure of a cumbustion cannon?

Posted: Thu Nov 30, 2006 4:24 pm
by Pete Zaria
According to my math, my cannon (metered propane, two spark gaps, camera flash ignition, 250ci chamber, 7ft 1.5" barrel) makes approximately 85PSI.

"Perfect" (stoichiometric) propane combustion makes 102psi. Achieving this means perfect conditions, perfect fuel/air mixture, perfect temperature and pressure, perfect ignition, etc... so it's very unlikely that anyone will actually see a 102psi combustion outside of a laboratory.

This question has been asked many times before. Use the search function next time, please :P

Peace,
Pete Zaria.

Edit: BLB pointed out to me that I should specify, that 102PSI is in PSIA, not PSIG. PSIA (or pounds per square inch Absolute) is the measurement of the actual pressure, while PSIG (pounds per square inch Gauge) is what a pressure gauge reads. However, normal atmospheric pressure is roughly 14.7psi, while a pressure gauge reads 0 at atmospheric pressure. Thus, measurements in PSIG are roughly 14.7psi below measurements in PSIG.

Posted: Thu Nov 30, 2006 10:42 pm
by kris
cool thanks for the info :D :D :D