feat(separator): physics-based outlet pressure drop from mechanical d…

[dupuypablo]

…esign

Add a stateless SeparatorPressureDropCalculator that derives the gas-side outlet pressure drop from the existing mechanical design. Three contributions are modelled and reported as an immutable PressureDropBreakdown:

• Inlet expansion: Borda-Carnot (1 - A_n/A_v)^2 . 0.5 . rho . v_n^2 when no inlet device is fitted, otherwise the inlet device's existing K-factor (no double-counting). Override via SeparatorMechanicalDesign.setInletExpansionLossCoefficient(K).

• Internals: mist eliminator Eu . 0.5 . rho_g . v_g^2 (existing setMistEliminatorDpCoeff, default 0.5 for knitmesh on scrubbers); demisting cyclone bank Eu . rho_g . v_cyc^2 on GasScrubber (existing setCycloneEulerNumber, default 4.5).

• Outlet contraction: K_con . 0.5 . rho_g . v_out^2, sharp-edged default 0.5; override via setOutletContractionLossCoefficient(K).

Wired into Separator via setEnhancedPressureDropCalculation(true). Off by default; existing simulations are unchanged. When enabled, run() overrides the static pressureDrop with the computed total and exposes the breakdown via getLastPressureDropBreakdown(). Calculator failures fall back to the static value silently. Includes unit tests covering Borda-Carnot, inlet device K, sharp-edged outlet K, user override, scrubber mesh + cyclones aggregation, outlet pressure consistency, and serialisability.

Pull Request

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