Controlling factors of pressure-coupled combustion responses in a high pressure combustion chamber

The purpose of this paper is to investigate the general characteristics and controlling factors of pressure-coupled combustion responses in a liquid propellant rocket engine, where the evaporation processes of hydrocarbon fuels will be numerically calculated directly using arbitrary forcing functions. The behavior of hydrocarbon droplets perturbed by acoustic pressure is analyzed and generalized with a parametric study. The effects of major design factors of a liquid rocket engine such as operating pressure and temperature, initial droplet size and droplet temperature are estimated as well as the driving frequency and amplitude of pressure perturbation. Results show that the operating pressure and driving frequency have an important role in determining the amplitude and phase lag of a combustion response. On the other hand, gas temperature, initial droplet size and droplet temperature, and amplitude of pressure perturbation cause only a minor change to the magnitude of combustion responses or behavior in the short initial stage. Resultant changes in the phase lag of heat of vaporization and thermal waves highly influence the magnitude and phase of combustion responses.