Laser-Based Measurements of OH, Temperature, and Water Vapor Concentration in a Hydrocarbon-Fueled Scramjet (POSTPRINT)

摘要

Two laser-based measurement techniques are implemented in a direct- connect hydrocarbon-fueled scramjet combustor. Planar laser-induced fluorescence (PLIF) of the OH radical is used to examine the flame structure within the combustor. Tunable diode laser-based absorption spectroscopy (TDLAS) is used to measure water vapor concentration and static temperature near the combustor exit. Combined with conventional measurements and Reynolds-averaged CFD simulations, these optical diagnostic techniques significantly enhance the information that is obtained from the scramjet combustor. Wall pressure data show the combustor to be operating in dual-mode with two regions of elevated pressure corresponding to the primary and secondary flameholding zones. The OH radical is well-distributed across the combustor with high OH concentrations occurring along the body, side, and cowl walls. TDLAS measurements indicate non- uniform body-to-cowl profiles in both temperature and water concentration. Near- wall regions are found to be the hottest while the core region is cooler.