Flowstead v3.1.1

Flowstead v3.1.1 (app version 3.1.1).

Fire relief on wet gas vessels, and a correct latent heat

• Fire on a vessel of saturated gas, such as a wet instrument-air receiver, now boils the water that collects at the bottom. If the contents are all vapour at operating conditions but you give a liquid level, and the gas is at its dew point (within 5 K), the liquid is taken as the condensate (the dew-point liquid). It is sized with API 521's wetted-fire method, as in HYSYS. A dry gas stays gas-filled whatever level you enter, with a warning. A 1.29 m × 1.84 m air receiver with 0.3 m of water, set at 10 barg, now needs a 1D2 valve, the same as HYSYS. Before, it got 1½F2 from the unwetted-wall method.
• The fire case's latent heat is right when the liquid holds dissolved gas. It used to be the enthalpy of the first 5 % vaporised, measured from the bubble point. A trace of dissolved light gas pulls the bubble point far down, so that figure included sensible heat. For water with a trace of dissolved air at 13 bar it gave 14.6 MJ/kg, about seven times too high, and the relief load came out seven times too small. It is now the enthalpy of the next 5 % (5 % to 10 % vaporised): 2.04 MJ/kg against 1.96 MJ/kg from the steam tables. This affects any fire case on a liquid with dissolved light ends, such as a separator's liquid.
• The exposed area of a gas-filled vertical vessel now includes the top head, as API 521 asks for (when it is within 7.6 m of grade). Before, it was left out, so the fire load was low. For the receiver above, the area is now 11.06 m² instead of 9.26 m².

Install: download flowstead-v3.1.1.apk on your Android phone (Android 8.0 or newer, 64-bit), open it and allow installing from this source.

Coming from a 0.x test build? Those were signed with the public debug key and this release is signed with the release key, so Android can't install it over them: export each project you want to keep (project menu → Export DWSIM file), uninstall the old app, install this one and import the files (Projects → Import DWSIM file). Data-sheet fields and line-sizing criteria are not part of a DWSIM file. Later releases install as updates.

Solves on the phone: DWSIM runs on the device (Settings → Engine → On this phone, the default); the first solve after starting the app takes a few seconds while DWSIM loads. A remote Flowstead engine (docs/engine-setup.md) is optional.

Release certificate SHA-256: d7883cfc24f1cb62db989086d69d217beed109b5b84164ff5394ad9e3e0bb921. flowstead-v3.1.1-mapping.txt de-obfuscates crash reports. Status and known limitations: docs/STATUS.md.

Commit: 01017ea