Blowdown Calculations Using HYSYS

Dear all,

Could you please help me with the following query:

Now I am doing the blowdown calculations for the gas injection manifold. It is 16" Manifold with 10 meters line with enlarger at the end (increasing line size to 6") and blowdown orifice on the 6" line. Is it possible to use the depressuring utility in HYSYS to calculate the blowdown time and final temperature, taking into account that flow upstream of orifice can be already choked?

Thanks in advance.