Experimental study of mixing and combustion processes in a solid propellant ducted rocket motor

Solid-propellant ducted rocket (SDR) has been long considered as a promising air-breathing propulsion system due to it high propulsion performance. The physical-chemical processes involved in the mixing and combustion processes in SDR combustion chambers are extremely complicated. Current literature on SDR systems sheds little light on these complex flow phenomena. Furthermore, the few available computational analyses of this problem are yet to be validated due to the lack of suitable experimental data. The purpose of this experimental investigation is to achieve a better understanding of the mixing and combustion processes in SDR combustion chambers.; In this study, several flow visualization techniques, including schlieren photography, laser light-sheet, and surface flow visualization techniques, are employed to study the cold flow characteristics in various SDR combustion chambers. Both two- and three-dimensional cases are investigated. In addition, a Laser Doppler Velocimeter (LDV) system is used for the measurement of cold flow velocities and turbulence correlations within the SDR combustor. Instrumentation is also set up to measure the pressure, temperature, and flow rates of the gases in the vitiator, gas generator, and main combustor for cases with combustion. A manual/auto control system for compressed air together with a liquid fuel supply system have also been designed and developed.; The qualitative results obtained from the schlieren, laser light-sheet,and surface flow visualizations, and the quantitative data obtained from the laser Doppler velocimetry measurements and combustion tests are not only helpful in understanding the mixing processes and flow structures in the combustor, but are also useful for partial validation of a theoretical model developed in a parallel program of the same research team. The experimental data are in good agreement with the predictions of the theoretical model. After validation by results presented in this thesis, the model can serve as a useful tool in the design and development of SDR propulsion systems.