Chapter 16 – COMBUSTION AND MIXING CONTROL STUDIES FOR ADVANCED PROPULSION

This chapter demonstrates the potential of applying combustion and mixing control to advanced propulsion systems. A number of experiments have been conducted and several experimental rigs have been constructed under the United States Office of Naval Research (ONR) combustion control program. The chapter discusses the four sets of experimental and analytical studies that have been conducted to identify the key physical mechanisms for controlling mixing and combustion processes in ramjet and scramjet combustors. The first set of experiments was used to study the interaction between periodic vortex structures and unsteady heat release processes, which may occur under certain operating conditions. The results from these controlled experiments were used to identify the spatial distribution of controller full in vortex, necessary to obtain active combustion control. The results were also tested in the second set of experiments, involving liquid-fueled active combustion control in a larger-scale dump combustor. The third study utilized the existing data on heated inlet experiments to model the liquid-fueled active combustion control process and to identify the amount of controller fuel flux required for control. Lastly, a supersonic mixing-enhancement experiment was conducted to assess the practicality of utilizing passive acoustic excitation as a means to enhance mixing in a scramjet.