Diode-laser mass flux sensor measurements are performed with a readout rate of 1 Hz in a Pratt and Whitney turbofan aeroengine during ground testing. The installation of the fiber-coupled sensor into the engine is described. The sensor's line-of-sight path has significant deviations from a uniform flow, and potential errors from these nonuniformities in the magnitude and direction of the velocity are investigated. The velocity is inferred from the Doppler shift of the wavelength-scanned line shape of molecular oxygen absorption near 764 nm using wavelength-modulation spectroscopy with detection at twice the modulation frequency (2f). The distortion of the wavelength-modulation spectroscopy-2f line shape from variations in the magnitude of the velocity is found to be small at subsonic velocities, which leads to accurate determination of the line center of the Doppler-shifted line shape. The apparent velocity is then corrected to account for nonuniformities using potential flow approximations. With this correction, the diode-laser sensor agrees (about 1%) with concurrent measurements of the calibrated mass flow to the aeroengine.
Diode-laser sensor for air-mass flux 2: Nonuniform flow modeling and aeroengine tests
Laserdiodensensor für Luft-Massen-Strömungen 2: Modellierung nicht-gleichförmiger Strömungen und Flugzeugtriebwerkstest
AIAA Journal (online) ; 45 , 9 ; 2213-2223
2007
11 Seiten, 12 Bilder, 3 Tabellen, 9 Quellen
Article (Journal)
English
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