Dear All, i am dealing with the orifice plate design for natural gas depressurization of an amount of pipe. I have calculated the process from 100 barg to 6 barg of internal pressure of the pipe. The outside pressure is atmosferic pressure let say 1 barg.

I have studied with the formulae of ISO but I need to know all the data on the time during all the depressurization process (pressure, temperature, flow, velocity, etc...) upstream and downstream of the orifice. The most difficult is to obtain the temperature downstream (the regime is supersonic, the study should be compressible, etc...) I have found some info on fluids mechanic for convergent nozzles but I did not found nothing from the process point of view of plants.

Could somebody inform me or let me a link to a book that show in deep the processes that occurs in the study of an orifice plate and the measures to take when needed to use some orifice plates in serial (separation, etc...)

Thanks in advance