Where would I find a comprehensive method for calculating the pressures and temperatures vs time resulting from blowdown and pressurising of pipelines and compressor stations?
I think you are more likely to get good answers to this question if you post in the "Piping and fluid mechanics engineering" forum. There are a few NG people who hang out there. They may see your post here, but I think that you would more luck over there.
Its quite a coincidence to see you here - I surfed into your web site purely by chance yesterday. Very nice!
MOC, the method of characteristics is probably the best technique to analyze flow problems in which pressure and temp are fuctions of location and time, ie x and t.