Review on the Dynamic Characteristics of Liquid Rocket Engine Injector

The dynamic characteristics and jet atomization performance of liquid rocket engine injectors are of great significance for the stable operation of liquid rocket engines. This paper provides a review of the dynamic characteristics of liquid rocket engine injectors and the study of spray field dynamics. Firstly, the role of injectors in the spray and combustion of engine combustor was overviewed. Then, theoretical researches on the dynamic characteristics of various typical injectors were discussed. Subsequently, experimental studies on the dynamic characteristics of injectors under atmospheric pressure, backpressure, and trans-/supercritical conditions were discussed. After that, the research progress on the spray field dynamics under unsteady inflow conditions and under external field excitation were elaborated. Finally, a summary was made and suggestions were proposed for future research. It is urgent to expand the injector dynamics theory to the field of cryogenic fluids under trans-/supercritical conditions in the future. The dynamic characteristics of injection and combustion of cryogenic fluids (such as liquid nitrogen, liquid oxygen, liquid hydrogen, methane, etc.) for trans-/supercritical conditions during incoming flow pulsation need to be studied. A more systematic and comprehensive theoretical study should be conducted on the unsteady atomization problem of gas–liquid coaxial injectors.