Combustion Toolbox

A MATLAB-GUI based tool for solving gaseous combustion problems

Combustion Toolbox is a a MATLAB-GUI based tool for solving gaseous combustion problems.

Website: https://combustion-toolbox-website.readthedocs.io

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
• 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, Caltech’s Shock and Detonation Toolbox, and TEA
• All the routines and computations are encapsulated in a more comprehensive and user-friendly GUI
• There is an early stage version in Python
• Display predefined plots (e.g., molar fraction vs equilence ratio)
• Export results in a spreadsheet
• Export results as a .mat format

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 and overdriven detonations
• Reflected detonations
• Oblique shocks/detonations
• Shock polar 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)