Measurements of OH and H2O for reacting flow in a supersonic combusting ramjet combustor

Mixing and combusting high-enthalpy flows, similar to those encountered in supersonic combusting ramjet engines, were investigated using a shock tunnel to produce the flow in conjunction with nonintrusive optical diagnostics that monitored the performance of two injector configurations. The shock tunnel was configured to produce Mach 3 flow and stagnation enthalpies corresponding to flight equivalent Mach numbers between 7-11. A pulsed hydrogen injection capability and interchangeable injector blocks provided a means of examining high-speed, high-enthalpy reacting flows. Planar laser induced fluorescence of OH radicals in the near-injector region produced images that show the combusting and mixing zones for the reacting flow. Line-of-sight exit plane measurements of water concentration and temperature were used to provide a unique method of monitoring exit plane products. Near-injector mixing dynamics and exit plane compositions were compared for wall jet and axial injection systems. In addition, exit plane measurements indicated that a quasi-steady-state condition was achieved during the 1- to 2-ms test times.