Numerical Analysis of Combustion Thermodynamics and Kinetic of Liquid Propellant Based on Hydrogen and Methane

The adequate understanding of sustained combustion and performance control in liquid propulsion engines requires sufficient knowledge about combustion chamber conditions, a series of chemical reactions that occur in the combustion chamber, and the thermo-physical variables based on the chemical reactions. For this purpose, after studying the governing equations and simulating the combustion chamber in different equivalence ratios, the distribution of temperature, chemical reaction rate, and mass fraction of chemical species are presented as the foundation for the challenges of the combustion chamber and related systems design. The simulation results desirably predict and justify many properties related to hydrogen-oxygen and methane-oxygen propellants. For methane-oxygen propellant due to the production of carbon monoxide at high ratios of fuel to oxidizer, a decrease in specific impulse, temperature, and chemical reaction rate of propellant is observed in the combustion chamber. The maximum temperature in the combustion chamber and the areas near the injectors for this propellant is much higher than the hydrogen-oxygen propellant at the equivalence ratio equal to one. Higher temperatures can cause serious harm to the combustion chamber wall, propellant transmission system, and injectors. Improving the nozzle design can also convert the thermal energy of the combustion gases into kinetic energy and velocity and can increase the specific impulse.