How can you have a larger pressure at the outlet then the inlet. In theory, air moves from higher to lower pressure, and not lower to higher pressure. The reason I ask this is, because I am working on a similar project and getting Pe > Pi which does not give me a Mach number of one at the throat ( I am doing the same calculations as you with different numbers). That said, if I change Pe to be 10kPa less the Pi I am getting a Mach number of 1 at the throat. Why 10kPa, I am not sure it was a random guess to get Pe < Pi. All that to say would you know of a way to calculate a value of Pe that is lower then Pi.
How can you have a larger pressure at the outlet then the inlet. In theory, air moves from higher to lower pressure, and not lower to higher pressure. The reason I ask this is, because I am working on a similar project and getting Pe > Pi which does not give me a Mach number of one at the throat ( I am doing the same calculations as you with different numbers). That said, if I change Pe to be 10kPa less the Pi I am getting a Mach number of 1 at the throat. Why 10kPa, I am not sure it was a random guess to get Pe < Pi. All that to say would you know of a way to calculate a value of Pe that is lower then Pi.