Gas expansion temperature

[ssk]

Hi everybody,
If there is a gas expansion from 20 bar to atmosphere (1bar), the temperature what we find from isentropic expansion equations is that at the throat of the valve/opening. How to find out the final temperature after it gets discharged to atmosphere? Does the temperature depend on the amount of gas expanded?
thanks
ssk

[carlo.stenali]

that depends from the way you decide to model the nozzle,
I utilize the isentropic nozzle model
available in PRODE PROPERTIES , see

'http://www.egpet.net/vb/entries/82303-PSV-sizing-with-HEM-%28Homogeneous-Equilibrium-Model%29-limits-of-application'

this model for HEM adopts a mixed (isentropic + adiabatic) solution for outlet temperature,
according my experience the results are consistent with infield measurements.