Liquid-propellant rocket engine injector dynamics

The dynamic characteristics of liquid-rocket injectors in the presence of i ntense combustion-chamber and propellant feed-line oscillations are discuss ed. Liquid-propellant injectors always function in nonsteady now environmen ts and are therefore considered as a dynamic component of an engine. In add ition to its main function of injecting propellant and preparing a combusti ble mixture, an injector simultaneously acts as a sensitive element that ma y generate and modify now oscillations because of its intrinsic unsteadines s and interactions with the combustion-chamber and feed-system dynamics. Th is paper also addresses nonlinear effects of nonstationary processes occurr ing in injectors. Various mechanisms for driving self-pulsations in both li quid and gas-liquid injectors are summarized systematically. A vital proble m of bifurcational unsteadiness of injector operation is considered.