DIODE LASER-BASED AIR-MASS FLUX SENSOR FOR SUBSONIC AEROPROPULSION INLETS

An optical air mass flux sensor based on a compact, room-temperature d iode laser in a fiber-coupled delivery system has been tested on a ful l-scale gas turbine engine. The sensor is based on simultaneous measur ements of O-2 density and Doppler-shifted velocity along a line of sig ht across the inlet duct. Extensive tests spanning engine power levels from idle to full afterburner demonstrate accuracy and precision of t he order of 1-2% of full scale in density, velocity, and mass flux. Th e precision-limited velocity at atmospheric pressure was as low as 40 cm/s. Multiple data-reduction procedures are quantitatively compared t o suggest optimal strategies for flight sensor packages. (C) 1996 Opti cal Society of America