SPECIES MEASUREMENTS IN A HYPERSONIC, HYDROGEN-AIR, COMBUSTION WAKE

A continuously sampling, time-of-flight mass spectrometer has been use d to measure relative species concentrations in a two-dimensional, hyd rogen-air combustion wake at mainstream Mach numbers exceeding 5. The experiments, in a free piston shock tunnel, yielded distributions of h ydrogen, oxygen, nitrogen, water, and nitric oxide at stagnation entha lpies ranging from 5.6 MJ kg(-1) to 12.2 MJ kg(-1) and at a distance o f approximately 100 times the thickness of the initial hydrogen jet. T he amount of hydrogen mixed in stoichiometric proportions was approxim ately independent of the stagnation enthalpy, despite the fact that th e proportion of hydrogen in the wake was increased with stagnation ent halpy. Roughly 50% of the mixed hydrogen underwent combustion at the h ighest enthalpy. The proportion of hydrogen reacting to water could be approximately predicted using reaction rates based on mainstream temp eratures.