Combustion of Hydrogen in a Two-Dimensional Duct With Step Fuel Injectors

摘要

An investigation of the combustion of hydrogen perpendicularly injected from step fuel injectors into a Mach 2.72, 2100 K vitiated test gas was con ducted. The model simulated the flow between the center and side struts of an integrated scramjet module at Mach 7 flight and an altitude of 29 km. Parametric variation included equivalence ratio, fuel dynamic pressure ratio, and area distribution of the model. The overall area ratio of the model was held constant at 2.87. Data acquired were wall static-pressure distributions, heat-transfer distributions, total heat transfer to the model, and pitot and gas concentration measurements in the model exit. The data analysis indicated that no measurable improvement in mixing or combustion efficiency was obtained by varying the fuel dynamic pressure ratio from 0.79 to 2.45. Computations indicated approximately 80 percent of the fuel was mixed so that it could react;however, only approximately 50 percent of the mixed fuel actually reacted in two test configurations, and 74 percent in later tests where less area expansion of the flow occurred. A possible reason for the poor reaction (50 per cent) is believed to be associated with adverse pressure interactions of the upstream injection process upon the downstream injection region. One-dimensional analysis also suggests that flow expansion tended to suppress the rate of reaction. The inability of the sample probe to quench the reaction in the gas samples prevented determination of local combustion efficiencies. Recommendations for future work are also discussed.