Physical Hypothesis for the Combustion Instability in Cryogenic Liquid Rocket Engines (Preprint)

摘要

In this work, the author would like to portray a sketch of a unified physical picture to describe the coupling nature/strength between the chamber acoustics and the injectors. This new perspective is achieved through a physically intuitive argument combined with previously published test results for two popular injector designs, namely, coaxial and impinging jets. For the impinging-jets injectors, it is shown that the dynamic behavior of the dark- core (or breakup) zone for each jet, their lengths and thicknesses, has a profound impact on injector 'sensitivity' to disturbances in its surrounding. This information is used to offer a possible explanation for the trends seen on the Hewitt stability plot in impinging-jet injectors.