Property flash workflows proven by tests

ThermodynamicOperationsTest exercises NeqSim’s property flash API across PT/TP orderings, unit handling, and online composition updates. This guide distills the tested patterns so you can set up property flashes with confidence.

PT vs TP flash symmetry

testFlash creates a binary methane/ethane SRK system and runs both flash(FlashType.PT, P, T, unitP, unitT) and flash(FlashType.TP, T, P, unitT, unitP) on the same state, then compares all returned properties for equality.【F:src/test/java/neqsim/thermodynamicoperations/ThermodynamicOperationsTest.java†L25-L48】 The test verifies that property flashes are order-invariant when pressure and temperature units are supplied explicitly.

Takeaway: You can interchange PT and TP flash modes without changing results, as long as you reinitialize (init(2) and initPhysicalProperties()) before reading properties.

Validating request inputs

testFluidDefined builds several SRK air mixtures and calls propertyFlash with streaming pressure/temperature vectors and optional online compositions to mimic live analyzers.【F:src/test/java/neqsim/thermodynamicoperations/ThermodynamicOperationsTest.java†L50-L119】 The test first omits init(0) to prove the API returns a descriptive error ("Sum of fractions must be approximately to 1 or 100..."), then reinitializes and confirms all calculation errors are null.

Setup checklist from the test:

1. Add components and set a mixing rule plus any volume corrections.
2. Call init(0) before requesting properties to normalize molar fractions.
3. Pass FlashMode 1, 2, or 3; any other mode yields the explicit error asserted in testNeqSimPython.【F:src/test/java/neqsim/thermodynamicoperations/ThermodynamicOperationsTest.java†L120-L152】
4. When streaming online composition updates, make sure each inner list matches the length of the pressure/temperature vectors.

Integration pattern for external clients

testNeqSimPython and testNeqSimPython2 illustrate how property flashes can be called from foreign interfaces (e.g., Python bindings) while maintaining result integrity.【F:src/test/java/neqsim/thermodynamicoperations/ThermodynamicOperationsTest.java†L120-L209】 The tests check that:

• Returned CalculationResult objects are stable under equality and hashCode() comparisons.
• Invalid FlashMode inputs return clear error strings without throwing exceptions.
• Property arrays cover the full set of SystemProperties.getPropertyNames() even when only single-point requests are made.

When wrapping the API externally, mirror these assertions to guard against transport or serialization errors.