SUPERSONIC COMBUSTION: ENHANCED IGNITION MIXING FLAME HOLDING AND DIAGNOSTIC CONCEPTS

WE PROPOSE A THREE PART, PHASE I, PROGRAM OF DIRECT INTEREST TO SCRAM JET COMBUSTOR DESIGN WHICH LAYS A PROPER FOUNDATION FOR HIGH-ENTHALPY,SUPERSONIC COMBUSTING FLOW EXPERIMENTS SUITABLE FOR A PHASE II PROGRAM. BOTH PHASE I AND II RESEARCH EFFORTS FOCUS ON FUEL/AIR MIXING, WHICH WILL SIGNIFICANTLY AFFECT IGNITION AND FLAME HOLDING PERFORMANCE. A SPECIFIC INJECTOR CONFIGURATION, WHICH PRODUCES INTERSECTING OBLIQUE SHOCKS, AND ITS PERFORMANCE, WILL BE THE PRIMARY OBJECT OF STUDY; THIS INTERSECTING SHOCK FLOWFIELD HAS BEEN DEMONSTRATED TO PRODUCE ENHANCED MIXING IN SUPERSONIC FLOW DIFFUSION LASERS. THE PROPOSED CONFIGURATION HAS THE POTENTIAL OF PRODUCING ENHANCED IGNITION DUE TO INCREASED AIR TEMPERATURE IN ADDITION TO A STABLE, FLAMEHOLDING TYPE OF FLOW. HIGH-SPEED, COLD FLOW FUEL/AIR MIXING EXPERIMENTS, PERFORMED IN A SUPERSONIC NOZZLE, WILL OCCUPY THE BULK OF THE PHASE I EFFORT. PRIMARY EXPERIMENTAL DIAGNOSITCS ARE INTERFEROMETRY FOR SHOCK WAVE IDENTIFICATION AND DENSITY GRADIENT MAPPING IN ADDITION TO LASER-INDUCED FLUORESCENCE TO QUANTIFY THE MIXING OF PRESSURE EFFECTS UPON OH EMISSION TO SPECIFY SENSITIVITY REQUIREMENTS FOR A HIGH SPEED COMBUSTING FLOW OPTICAL DIAGNOSTIC AND A DETAILED SHOCK TUNNEL NOZZLE DESIGN FOR THE HIGH-ENTHALPY COMBUSTION FLOW EXPERIMENTS.