Real gas calculations

Robert Helling helling at atdotde.de
Thu Jan 12 12:30:26 PST 2017


Hi,

I just wanted to report that I am now convinced by Linus’ calculations of the real gas corrections (and also how a 4% correction at 200bar) can lead to an 8% correction to the SAC when the gas use is 200bar -> 100bar.

So I incorporated this corruption also in the planner (pull request is on github). But I am not sure that this should go into the upcoming release, since my testing due to time constraints was rather limited.

Things that once might do in a similar direction in the future:

1) Correct the pressure interpolation for the profile to take into account the z factor (so that the rate of drop in pressure is higher for fuller cylinders assuming constant SAC and depth)

2) Add a user option in the preferences to turn off the real gas correction (for users who want to see agreement with their naive ideal gas calculations). The way to do that would be to make the gas_compressibility_factor() always return 1.0 when set to ideal gas.

Best
Robert
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