Compact, Low Cost Instrument for Simultaneous Temperature, Velocity, and H2O Density Measurements in a Supersonic Propulsion Exhaust Nozzle

Physical Sciences Inc. (PSI) proposes to demonstrate a low-cost, compact, rugged instrument for simultaneous measurements of static temperature, velocity, and H20 density in the exhaust nozzle of a supersonic propulsion engine. The measurements will be based on room temperature, tunable diode laser absorption measurements using recently available InGaAsP lasers. Aunique, low-cost, and simple noise canceling detector (NCD) will be used to provide near shot-noise-limited performance for highly accurate measurements without the complexity and cost associated with frequency modulation (FM) absorption techniques. The NCD also permits use of low-cost, commercially available InGaAsP lasers rather than custom-fabricated, long-wavelength devices. The resulting system is pressure-independent, simpler to use, and lower cost than comparable FM-based systems. The Phase I portion of the program will demonstrate quantitative, simultaneous H20 density and temperature measurements over the range of temperatures expected in a combined-cycle Mach 6 exhaust nozzle. In Phase II, a prototype instrument for simultaneous H20 density, temperature, and velocity will be delivered and integrated with the Air Force High Mach Advanced Research Test Facility.