NAVRONIS Propulsion Toolkit
Live Sizer Verification (62 Tests) 4 Injector Types CAD Geometry CLI & Code GitHub
v0.4.0 Open-Source Release β€’ 35 Unit Tests (100% Pass Rate)

First-Principles Liquid Rocket
Propulsion Analytical Toolkit

Zero black boxes. Zero hardcoded outputs. Dynamically calculates choked sonic throat, chamber barrel, Bartz heat transfer, acoustic cavity buzz, and the 4 canonical injector families.

Try Live Sizer View on GitHub

⚑ Real-Time Rocket Engine Sizer (Combustor & Injector)

Calculates the Combustor (Day 1) and the 4 Canonical Injectors (Day 2) simultaneously from first principles.

Day 1: Combustor Day 2: Injectors Day 3: Regen Cooling Day 4: Nozzles Day 5: Cycles & Orbit Day 6: Benchmarks & Throttling
🎯 Flight Engine Reference Presets (Day 6)

Load test-stand parameters for iconic flight engines (<5% validation error against NASA/literature).

πŸ“‰ Off-Design Throttling & Acoustic Chugging (Day 6 / NASA SP-194) 100% Throttle (Full Power)
SAFE (dP/Pc ≥ 15%)
ATTACHED (No Shock)
βœ“ Sizing & 3D Model Synced
Auto-updates on keystroke & value change
πŸ”₯ Combustor & Operating Inputs (Day 1)
πŸ’§ Injector Head Inputs (Day 2)
❄️ Regenerative Cooling Jacket Inputs (Day 3)
πŸš€ Supersonic Nozzle & Altitude Inputs (Day 4)
⚑ Turbomachinery, Power Balance & Flight Inputs (Day 5)
πŸ”₯ 1. Combustor & Chamber Sizing Results (Day 1) NASA SP-125 / Bartz / NASA SP-194
Throat Diam (Dt)
42.65 mm
Combustor Diam (Dc)
91.48 mm
Contraction Ratio
4.60
Barrel Length (Lcyl)
193.6 mm
Total Combustor Lc
235.9 mm
Combustor Volume
1.43 L
Stay Time (Ο„s)
1.35 ms
1T Buzz Frequency
8014 Hz
Peak Bartz Flux
28.4 MW/mΒ²
Min Liner Wall
2.94 mm
πŸ’§ 2. Injector Head & Atomization Results (Day 2) Yang (2004) / Bazarov / Dressler / Rupe
Total Mass Flow
10.37 kg/s
Ox / Fuel Flow
8.07 / 2.30 kg/s
Injector Delta P
24.0 bar (20%)
Post Inner Diam
3.12 mm
Annular Gap / Sheet
0.24 mm
Momentum Ratio J
9.35
Droplet SMD (D32)
29.8 Β΅m
Chugging Margin
PASS (β‰₯15%)
❄️ 3. Regenerative Cooling & Conjugate Thermal Results (Day 3) Gnielinski (1976) / Haaland (1983) / NASA SP-8087
Throat Channel Width
0.88 mm
Channel Aspect Ratio
2.06
Coolant Velocity
50.9 m/s
Reynolds Number
230,000
Enhanced Coolant HTC
181.9 kW/mΒ²-K
Hot-Gas Wall Temp (Twg)
698 Β°C (971 K)
Coolant Wall Temp (Twc)
306 Β°C (579 K)
Coolant Delta P
52.2 bar
Bulk Coolant Temp Rise
181.3 K
Thermal Stress Margin
PASS (Yield Safe)
πŸš€ 4. Supersonic Nozzle & Altitude Performance Results (Day 4) NASA SP-125 / Rao (1958) / Stark (2005) / 1976 US Standard Atmosphere
Exit Diam (De)
233.6 mm
Nozzle Length (Lnoz)
385.2 mm
Exit Mach Number
4.12
Exit Pressure (Pe)
20.5 kPa
Ambient Pressure (Pa)
101.3 kPa
Divergence Factor (Ξ»)
0.973
Boundary Layer Ξ΄*
1050 Β΅m
Delivered Thrust
28.4 kN
Delivered Isp (Flight)
276.5 s
Vacuum Isp (Space)
318.2 s
Flow Separation (Stark)
ATTACHED
⚑ 5. Turbopump Hydraulics & Cycle Power Balance (Day 5) Huzel-Huang (1992) / NASA SP-8107 / Sutton-Biblarz (2016)
Ox Pump Discharge
87.5 bar
Ox Pump Power
104.6 kW
Fuel Pump Discharge
112.0 bar
Fuel Pump Power
109.4 kW
Total Pumping Power
214.0 kW
Impeller Classification
Radial Centrifugal
Turbopump Weight
14.8 kg
Net Cycle Vacuum Isp
309.6 s
GG Flow Fraction / Loss
2.32% (-4.6 s)
Power Balance Status
PASS (Closed)
🌌 6. 2D Ascent Flight Mechanics & Orbit Simulator (Day 5) 1976 US Standard Atmosphere / NASA SP-8087 / Griffin & French (2004)
Liftoff T/W Ratio
1.52
Burnout Altitude
140.0 km
Burnout Velocity
3589 m/s
Burnout Mach
Mach 13.0
Flight Path Angle
57.5 deg
Max Dynamic Pressure (Q)
35.9 kPa (at 10.9 km)
Gravity Loss Ξ”V
1357 m/s
Aerodynamic Drag Loss
106 m/s
Delivered Net Ξ”V
3589 m/s
LEO Orbital Insertion (200 km)
4195 m/s deficit
πŸ“ Industrial Thrust Chamber 3D CAD Suite STEP / STL CAD SOLID

Direct 1:1 visualization of OpenCASCADE 3D STEP solid model with uniform hollow pressure vessel walls & true Rao contour.

CAD MODEL:
VIEW PRESETS:
SHADING: | SECTION CUT:
πŸ–±οΈ Drag: Orbit | Scroll: Zoom | Right-Drag: Pan
DATUM ORIGIN [0, 0, 0]
+X Thrust Axis [β„„] +Y Radial Vert +Z Lateral
ACTIVE CAD SOLID: OpenCASCADE 3D Solid (.step/.stl)
L_TOTAL: 521.0 mm | THROAT: βŒ€42.6 mm | EXIT: βŒ€233.6 mm
WALL: 3.0 mm Uniform Shell | MESH: 35,910 Triangles
πŸ’‘ Tip: Drag & drop any .STL or .STEP file directly into viewport
πŸ“Š Axial Physics Distributions along Engine Station x

Synchronized 1D differential curves: Isentropic Mach Number $M(x)$, Bartz Heat Flux $q(x)$, and Static Expansion Pressure $P(x)$.

x = 0 (Injector Face) x_cyl Sonic Throat x_t (M=1.0) Exit Lip x_e
Export Native Engineering CAD: Generate 3D STEP solids or SolidWorks coordinate curves.
πŸ“ Download 3D STEP Model (.step) πŸ–¨οΈ Download 3D STL (.stl for Windows 3D Viewer)

Automated Verification Matrix (127 Tests)

100% test coverage with zero heavy CFD binary requirements. 127/127 tests passing in 1.80s (100% verification rate).

Subsystem Test File Physics Covered Status
Day 1: Combustor test_chamber_and_combustion.py Choked throat continuity, Humble contraction, stay time, Vandenkerckhove gamma function PASSED
Day 1: Gas Dynamics test_aerodynamics_and_nozzle.py 1D isentropic Area-Mach root solving, divergence losses, Summerfield separation PASSED
Day 1: Thermal & Bartz test_bartz.py Bartz (1957) convective film HTC, sigma property variation factor, recovery temperature PASSED
Day 1: Cooling & Stress test_coolant_and_conduction.py Sieder-Tate, Ito curvature friction, radial Fourier conduction, ASME hoop stress PASSED
Day 1: API & Exports test_combustor_api.py High-level CombustorDesign facade, explain() literature provenance, JSON/CSV exports PASSED
Day 2: Hydraulics test_injector.py (Orifice & Chugging) Torricelli-Bernoulli continuity, NASA SP-194 chugging decoupling stiffness margin (≥ 15%) PASSED
Day 2: Coaxial & Swirl test_injector.py (Coaxial & Swirl) Momentum flux J, Lorenzetto-Lefebvre SMD, Abramovich swirl discharge, gas core, Lefebvre SMD PASSED
Day 2: Pintle & Doublets test_injector.py (Pintle & Impinging) Dressler/Heister TMR & spray cone angle, Rupe momentum balance, Ingebo breakup SMD PASSED
Day 3: Cooling Channels test_regen_channel.py Milled rectangular channels, Gnielinski HTC, Haaland friction, fin efficiency, 1D conjugate thermal closure PASSED
PR #9: Literature Audit test_audit_literature_limits.py Humble contraction limits, Huzel-Huang Eq. 4-5 closed-form identity, Bartz supercritical boundary PASSED
Day 4: Supersonic Nozzle test_nozzle.py 1D Area-Mach inversion, Rao 80% bell BΓ©zier contour, Stark (2005) tri-criteria separation, 1976 Standard Atmosphere PASSED
Day 5: Turbomachinery & Cycles test_cycle.py Pump hydraulics, specific speed Ns & Nss cavitation, turbine expansion, 5 power balance cycles (GG, Expander, SC, FFSC, Press-Fed) PASSED
Day 5: Ascent Flight Trajectory test_trajectory.py 2D Point-mass gravity turn powered ascent, transonic wave drag, Max Q dynamic pressure, orbital deficit & LEO payload PASSED
Day 5: Master Engine Architecture test_engine_system.py Unified Chamber + Injector + Regen + Nozzle + Turbopump + Flight synthesis, automated engine datasheets, JSON serialization PASSED
Day 6: Flight Engine Decks test_engine_deck.py Merlin 1D, Raptor 2, RS-25, RD-180, RL10, Rutherford, LMDE test-stand literature verification (<5% mean error) PASSED
Day 6: Throttling & Chugging test_throttle.py Quadratic ΔP ∝ τ², NASA SP-194 acoustic chugging decoupling (≥15%), Summerfield shock migration PASSED
Day 6: Electric Turbopump test_electric_pump.py BLDC motor power density (5.5 kW/kg), inverter efficiency, Li-ion battery pack energy (250 Wh/kg), zero-dump performance PASSED

The 4 Canonical Injector Families

Streamlined to the 4 essential injector designs that power 99% of liquid rocket propulsion.

COAXIAL

Shear Coaxial

High-velocity annular gas shears a central liquid core. Momentum flux ratio J checked against the stable 2-20 window with Lorenzetto-Lefebvre SMD atomization.

Engines: SSME, RL10, Vulcain, Raptor
SWIRL

Centrifugal Swirl

Tangential inlet ports spin liquid into a centrifugal sheet around an air/gas core with coaxial gas shroud. Sized via Abramovich & Lefebvre sheet breakup theory.

Engines: RD-170, RD-180, NK-33
PINTLE

Central Pintle

Single central deflective shaft. Outer annular fuel gap deflected by radial LOX slots. Total Momentum Ratio (TMR) defines spray cone half-angle beta.

Engines: Apollo LMDE, Merlin 1D, TR-106
IMPINGING

Unlike Doublet

Discrete intersecting liquid jets forming an atomizing fan. Sized with Rupe momentum balance for uniform O/F distribution and Ingebo breakup SMD.

Engines: Apollo SPS, Titan II, Viking

Direct CAD & Contour Export

From mathematical equations to dimensioned drawings and 3D solid CAD models in one command.

  • 2D Dimensioned Contour: Publication-quality PNG/SVG axial profiles.
  • Discretized Curves: JSON and CSV point arrays for SolidWorks, FreeCAD, and NX.
  • 3D STEP File Generation: Ready-to-run CadQuery Python script for CNC and 3D printing.
navronis --plot-save chamber.png --export-json chamber.json --export-cadquery step.py
Navronis 30 kN Combustor Cross Section

Zero-Code Command-Line Terminal

Execute complete preliminary sizing directly in your shell.

bash β€” navronis --subsystem injector --injector-type coaxial
$ navronis --subsystem injector --injector-type coaxial --thrust 30000 --pc 120 --propellants LOX/CH4

==============================================================================
NAVRONIS PROPULSION -- INJECTOR SIZING REPORT: COAXIAL
Propellant: LOX/CH4 | Thrust: 30.0 kN | Pc: 120.0 bar
==============================================================================
Mass Flow: Total = 10.370 kg/s (LOX: 8.066 kg/s, Fuel: 2.304 kg/s)
Injector Delta P: 24.00 bar (20.0% Pc)
Chugging Decoupling Margin: PASS (>=15%)
------------------------------------------------------------------------------
Elements: 19
Liquid Post ID: 3.12 mm
Liquid Post OD: 4.32 mm
Gas Sleeve ID: 4.79 mm
Annular Gap: 0.24 mm
Liquid Ox Velocity: 48.65 m/s
Gas/Fuel Velocity: 85.32 m/s
Momentum Flux Ratio J: 9.35 [Target: 2.0 - 20.0]
Velocity Ratio VR: 1.75
Recess Length: 4.68 mm
Droplet SMD (D32): 29.8 um
==============================================================================