v0.5.0 (Day 5) - Turbomachinery Cycles, Flight Trajectory & Unified Engine Architecture

?? Navronis Day 5 Release: Complete Turbomachinery Cycles, 2D Powered Ascent Simulator & Master Engine Architecture

After a one-week deep engineering sprint, Navronis Day 5 is officially launched! Day 5 marks the transition from individual component physics (combustor, injectors, cooling jacket, supersonic bell) to complete system closure and mission flight simulation.

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? What's New in Day 5 (v0.5.0)

1. ?? Turbomachinery & Power Balance Cycles (cycle.py)

• Centrifugal Pump Hydraulics: Head $H = \Delta P / (\rho g_0)$, shaft power $\dot{W}p = \dot{m} \Delta P / (\rho \eta_p)$, and impeller tip speed $u{tip}$.
• Impeller Classification: Specific speed $N_s$ automatically classifies radial centrifugal, mixed-flow, and axial impellers.
• Cavitation Prevention: Suction specific speed $N_{ss}$ and required Net Positive Suction Head ($NPSH_R$) inversion identities.
• Turbine Isentropic Work: Enthalpy extraction $\Delta h_{iso} = c_p T_{in} [1 - (1/PR)^{(\gamma-1)/\gamma}]$.
• 5 Canonical Engine Power Cycles Closed:
  1. Pressure-Fed Cycle: High-pressure inert gas tank blowdown and pressurant helium mass sizing.
  2. Gas Generator Cycle (Open): Turbopump shaft balance and exhaust dump specific impulse penalty $\Delta \text{Isp}$ (Merlin 1D / Vulcain style).
  3. Closed Expander Cycle: Regenerative cooling vapor heat extraction vs turbopump shaft power pinch-point margin (RL10 style).
  4. Staged Combustion Cycle (ORSC & FRSC): High-pressure preburner drive with zero dump loss (RD-180 & RS-25 SSME style).
  5. Full-Flow Staged Combustion (FFSC): Dual oxygen-rich and fuel-rich preburners driving separate turbopumps with gas-gas main injection (SpaceX Raptor style).

2. ?? 2D Powered Ascent Gravity Turn Flight Simulator ( rajectory.py)

• 2D Point-Mass Dynamics: Coupled numerical integration of thrust, weight, transonic aerodynamic drag, and pitch-over dynamics:
  \frac{dv}{dt} = \frac{F - D}{m(t)} - g \sin\gamma, \quad \frac{d\gamma}{dt} = -\left(\frac{g}{v} - \frac{v}{r}\right)\cos\gamma
• Transonic Wave Drag Curve: Continuous $C_D(M)$ modeling subsonic drag, transonic peak at Mach 1.05, and supersonic wave decay.
• 1976 US Standard Atmosphere: Continuous density and pressure fields from sea level to 85 km.
• Dynamic Pressure Max Q: Evaluates peak aerodynamic loading magnitude and altitude.
• Loss Accounting: Numerical bookkeeping of gravity loss $\Delta V_{grav}$, drag loss $\Delta V_{drag}$, and orbital deficit against a 200 km circular LEO target ($7784\text{ m/s}$).

3. ??? Unified Master EngineSystem Synthesizer (system.py)

• Connects Combustor (Day 1) + 4 Injectors (Day 2) + Regen Cooling (Day 3) + Rao Nozzle (Day 4) + Turbomachinery Balance (Day 5) + Flight Trajectory (Day 5).
• Generates aerospace-grade specification datasheets and serialized JSON configurations.

4. ?? Automated Test Suite Expansion (100 / 100 Tests Passing)

• Added 23 new test cases across est_cycle.py, est_trajectory.py, and est_engine_system.py.
• Total test count expanded from 77 to 100 tests (100% pass rate, 0 failures, 0 skips) executing in 1.51s.

5. ?? Interactive Web Simulator (docs/index.html) & CLI Updates

• Interactive UI updated with cycle selector, turbopump power gauges, and 2D flight ascent telemetry.
• CLI enhanced with --subsystem cycle, --subsystem trajectory, and --subsystem system.

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Primary Literature: Huzel & Huang (1992), Sutton & Biblarz (2016), Griffin & French (2004), NASA SP-125, SP-194, SP-8087, SP-8107, SP-8110.

Navronis v0.4.0 — Day 4: Supersonic Nozzle Aerodynamics & Altitude Engine

Navronis v0.4.0 — Day 4: Supersonic Nozzle Aerodynamics & Altitude Performance

We are thrilled to announce the Day 4 Public Release of Navronis (v0.4.0), expanding the liquid rocket propulsion preliminary sizing pipeline to high-speed exhaust expansion, supersonic contour generation, and trajectory altitude performance.

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What's New in Day 4 (v0.4.0):

1. 1D Isentropic Area-Mach Supersonic Inversion (NASA SP-125):

   • High-precision root solver mapping geometric nozzle area ratio $\varepsilon = A_e / A_t$ to supersonic exit Mach number $M_e$.
   • Static pressure ($P_e$), static temperature ($T_e$), and sonic exit velocity ($v_e$) across any arbitrary combustion gas combination.

2. Rao (1958) 80% Parabolic Bell Contour:

   • Quadratic Bézier parabolic spline connecting the circular throat arc ($ heta_n �pprox 30^\circ$) to a shallow exit lip angle ($ heta_e �pprox 8^\circ$).
   • Yields over 1% higher delivered thrust coefficient than a standard 15° cone of equivalent length.

3. 2D Divergence Loss Factor ($\lambda$):

   • Exact analytical model for conical nozzles $\lambda = (1 + \cos\alpha)/2$ and Rao parabolic bells using the mean-angle formulation.

4. Turbulent Boundary Layer Displacement ($\delta^*$):

   • Schlichting (1979) 1/7th-power turbulent boundary layer displacement thickness $\delta^* = \delta / 8$ and flow area blockage correction.

5. Stark (2005) Tri-Criteria Flow Separation Screening:

   • Evaluates Summerfield (1954), Schmucker (1973), and Kalt & Badal (1965) simultaneously.
   • Preserves rigorous physics closure: returns CONFLICT_UNRESOLVED when empirical models contradict rather than arbitrarily selecting a winner.

6. 1976 U.S. Standard Atmosphere Trajectory Solver:

   • Barometric altitude marching from sea level ($z = 0$) through the stratosphere ($z = 86\text{ km}$), computing ambient pressure, density, and delivered $I_{sp}(z)$.

7. Merged PR #9 from @tenten48tenten (Closes #1):

   • Contraction ratio bounds audit, Huzel-Huang Eq. 4-5 analytical closed-form equivalence, and supercritical Bartz property monotonicity.

8. Live Interactive Web App Update:

   • Dynamic SVG CAD rendering now visualizes the full supersonic nozzle bell contour to scale, with live altitude sliders and shock separation warning indicators.

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Verification:

• 62 / 62 Unit Tests Passing (100% pass rate in 3.15s).
• Full provenance transparency via .explain() on every computed parameter.