Combustion Toolbox: A MATLAB-GUI based open-source tool for solving gaseous combustion problems

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Main features

• The code stems from the minimization of the free energy of the system by using Lagrange multipliers combined with a Newton-Raphson method, upon condition that initial gas properties are defined by two functions of states (e.g., temperature and pressure)
• When temperature is not externally imposed, the code retrieves a routine also based on Newton-Raphson method to find the equilibrium temperature
• Solve processes that involve strong changes in the dynamic pressure, such as detonations and shock waves in the steady state
• Find the equilibrium conditions of the different phenomena undergoing behind the shock: molecular vibrational excitation up to dissociation, and electronic excitation up to ionization, thereby providing the properties of the gas in plasma state within the temperature range given by the NASA’s 9-coefficient polynomial fits.
• Calculate the chemical equilibrium composition of a mixture by selecting which species can react or remain chemically frozen (inert).
• The corresponding thermodynamic properties of the species are modelled with NASA’s 9-coefficient polynomial fits, which ranges up to 20000 K, and the ideal gas equation of state
• Results are in excellent agreement with NASA’s Chemical Equilibrium with Applications (CEA) program, CANTERA and Caltech’s Shock and Detonation Toolbox, and TEA

• Chemical equilibrium problems
  • TP: Equilibrium composition at defined temperature and pressure
  • HP: Adiabatic temperature and composition at constant pressure
  • SP: Isentropic compression/expansion to a specified pressure
  • TV: Equilibrium composition at defined temperature and constant volume
  • EV: Adiabatic temperature and composition at constant volume
  • SV: Isentropic compression/expansion to a specified volume
• Shock calculations:
  • Pre-shock and post shock states
  • Equilibrium or frozen composition
  • Incident or reflected shocks
  • Chapman-Jouguet detonations, overdriven detonations, and underdriven detonations
  • Reflected detonations
  • Oblique shocks/detonations
  • Shock/detonation polar curves for incident and reflected states
  • Hugoniot curves
  • Ideal jump conditions for a given adiabatic index and pre-shock Mach number
• Rocket propellant performance assuming:
  • Infinite-Area-Chamber model (IAC)
  • Finite-Area-Chamber model (FAC)
• All the routines and computations are encapsulated in a more comprehensive and user-friendly GUI
• The code is in it’s transition to Python
• Export results in a spreadsheet
• Export results as a .mat format
• Display predefined plots (e.g., molar fraction vs equilence ratio)

This project is also part of the PhD of Alberto Cuadra-Lara.