High-Frequency Combustion Instability in Liquid Propellant Rocket With Concentrated Combustion and Distributed Time Lag

Abstract

In view of the turbulent conditions in the combustion chamber in a liquid propellant rocket motor, different pro­ pellant elements wil] encounter different dynamic and heat transfer conditions before they are converted into burned gas. This fact is represented in the simplified model of analyzing high-frequency combustion instability assumed in Ref. (I)2 by the nonuniformity of the time lags and the space lags of different propellant elements. The effect of nonuniform time lag on the high-frequency insta­ bility of the system is analyzed with the spatial distribution of combustion assumed as concentrated at arbitrary axial location, i.e., uniform space lag. It is inferred from the analytical results that spreading the sensitive time lag about a mean value is stabilizing, but its over-all effect, especially for small time lag spread, is not very significant as compared with the stabilizing effect of the supercritical nozzle.