COMBUSTION INSTABILITY. ANALYTICAL SURVEY

Liquid rocket engines are subject to a wide variety of types of combustion instability. The two basic instability modes are chugging, a low- frequency instability mode which is caused by interaction between the chamber pressure and the injection flow rate fluctuations, and screaming, a more harmful high-frequency, acoustic instability mode which may lead to burnout of the motor due to increased heat flux. Only two articles on low-frequency instability were found in Soviet open literature. Experimental studies or analyses of high-frequency instability which take into account actual engine operation, i.e., mixing, evaporation, dissociation fuel atomization, etc., were not found in the literature surveyed. However, several theoretical studies were found which deal with highfrequency instability under idealized conditions. The majority of the Soviet studies included in this report deal with the interaction of shock and pressure waves with the flame front. These studies are of high phenomenological interest and are indirectly applicable to combustion stability analysis.