Experiments with a solid-propellant acoustic oscillator

An end-burning, side-vented, solid-propellant motor designed to produce essentially one-dimensional acoustic oscillations has been under development and test for the past three years. The immediate purpose of these investigations was to study the growth and decay of selfexcited, combustion-driven, acoustic oscillations in chamber pressure and to measure the effects of operating parameters upon the growth rates, amplitudes, and frequencies of the oscillations. An ultimate purpose is to use this information as a guide to the further development of a theory of solid-propellant acoustic combustion instability. The report presents certain results from current experiments in which an essential innovation was the use of a transparent quartz tube containing the propellant sample and serving as part of the combustion chamber during burning. (Author)