Tunable diode laser absorption sensor for temperature and velocity measurements of O2 in air flowsA fast and nonintrusive velocity and temperature diagnostic based on oxygen absorption is presented. The system uses a GaAlAs tunable diode laser, ramped and modulated in wavelength at high frequency. Detection is performed at twice the modulating frequency, leading to second harmonic absorption lineshapes. Velocity is inferred from the wavelength shift of the absorption line center due to the Doppler effect. Temperature is determined by comparing experimental and calculated lineshapes. Capabilities of the technique for studies of transient high-speed flows are demonstrated in shock tube experiments. Good agreement is obtained with predicted temperatures and velocities when pressure-induced shifts are accounted for.
Document ID
19910036847
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Philippe, L. C. (Stanford Univ. CA, United States)
Hanson, R. K. (Stanford University CA, United States)