Characteristics of Flashing Spary of Oxygen/Methane Engines in High-Altitude and Low-Pressure Environments

The propellant in the low-pressure combustion chamber of liquid oxygen/methane engines operating in orbit will undergo flashing. The subsequent ignition and combustion of the propellant can be significantly influenced by this flashing process. Therefore, to elucidate the effects of injector geometry and back pressure on the propellant's flashing behavior, a numerical model simulating the flashing of liquid oxygen within on-orbit engines has been developed in this study. The results indicate that the flashing process is sensitive to back pressure. When the back pressure is 0.2 kPa, the overall evaporation efficiency can reach 0.33199, which is 50.4% higher than the efficiency observed at a back pressure of 21 kPa. Additionally, increasing the diameter of the injector can moderately enhance droplet dispersion. In contrast, variations in the length of the inlet section have no significant impact on the flashing process of liquid oxygen.