First, I want to thank you sincerely for your answers.
Morten : I've tried to find on the web your referenced article but without results. Could it be possible for you to send me it ?
Sshep : You're right my description is too brief. So, my problem is this following one :
I try to develop a fortran program which could simulate an emergency depressurization of natural gas installations. My system can be described as :
capacity + restriction orifice + pipe leading to cold vent (some parts being underground and some being above ground level)
The results of this program run would have to include : time evolution of the capacity pressure and temperature, time evolution of the depressurization pipe material.
At this moment my strategy is :
for a discrete time evolution, compute the mass rate by : rate through orifice = rate through pipe which gives the good pressure drop in order to obtain a pressure of 1 atm at the outlet.
The problem is that temperature (and thus heat transfer through pipe wall) acts on the gas density (thus on the gas velocity and thus on the pressure drop).
I think it can be solved be finite elements. I wonder if this problem was solved before and if it can be possible to find the good solving strategy in a previous work ?
Best regards,
Silverstone