Flowstead v3.0.0

Flowstead v3.0.0 (app version 3.0.0).

Flowstead 3.0: now on DWSIM 10

• Every calculation now runs on DWSIM 10.2.12, the current generation of the open-source simulator, built by Flowstead from its published source, on the phone and on the engine server alike. DWSIM 9 receives no more updates; DWSIM 10 brings its fixes and opens the way to its newer features, such as distillation curves and product-quality column specifications, in later versions.
• Liquid densities are more accurate. Liquid mixtures (NGL, LNG, condensate, live oil) now use COSTALD, the method HYSYS uses for hydrocarbon liquids; pure and water-rich liquids keep experimental data. Against reference equations of state over 29 liquids the average error is 0.50 % (was 0.87 %) and the worst 1.9 % (was 5.4 %, a hot NGL). Liquid volume flows, separator levels and line sizing follow.
• PVT laboratory about 100 times faster. A saturation pressure takes about a second instead of up to two and a half minutes, with the same result. The PVT regression also tries finer steps before stopping, so it fits closer.
• Results change slightly with the new engine: mainly liquid densities and what depends on them (volumes, residence times, reactor conversions in a fixed volume). Every reference check (steam tables, hand calculations, published data) still holds; the details are in the project's decision log (D88–D94).
• Phases labelled by the fluid, both ways. A one-phase result is checked against the fluid itself: a dense gas at very high pressure (for example 320 barg) is reported as vapour, and a subcooled liquid that the flash called vapour is reported as liquid.
• Projects from earlier versions open as before, and so do DWSIM files saved by Flowstead 2.x (the nine kept for testing all open and solve). Files exported by 3.0 note that desktop DWSIM's default liquid densities can differ from Flowstead's for mixtures.
• Results a project kept from 2.x were solved on DWSIM 9: they show as out of date ("Solved with DWSIM 9 — solve again") until the flowsheet is solved again. If you run your own engine server, update it to 3.0 as well (the Docker image now builds DWSIM 10).
• Phase envelopes, bubble and dew points. Pure-fluid envelopes now end at the critical point, mixture critical points are closer to independent calculations, and every stream bubble or dew point is checked to lie on the phase boundary; near a mixture's critical point, where the flash cannot place it reliably, it is shown as missing (—) rather than guessed.
• Gas thermal conductivity at high pressure is now within a few percent of reference data (it was up to 20 % low).
• Thermal-expansion relief loads are slightly lower and closer to reference data (the liquid's expansion coefficient was 5–9 % high).

Install: download flowstead-v3.0.0.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-v3.0.0-mapping.txt de-obfuscates crash reports. Status and known limitations: docs/STATUS.md.

Commit: 910c9c8