Graduate Research Training in Advanced Diagnostics Techniques (AASERT)
Final rept. 1 Jun 1997-30 Nov 2000
STANFORD UNIV CA DEPT OF MECHANICAL ENGINEERING
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Tunable diode laser absorption probes have been developed for characterization of short-duration hypersonic flows produced in shock tunnels and expansion tubes. A new single-wavelength probe was tested in a large reflected shock tunnel at Calspan and in an expansion tube at Stanford. The demonstrated success of this sensor in characterizing the time evolution of freestream velocity should improve the utility of aerodynamic test data obtained in high-enthalpy hypersonic tunnels and should also provide a means of monitoring the effects of facility modifications aimed at increasing test time and flow steadiness. Good agreement was found over the full range of velocities observed up to 5.0 kmsec when the water vapor and potassium probes were employed simultaneously. Infrared PLIF imaging techniques have been developed for imaging of CO and CO2 in flames. These diagnostics employ tunable optical parametric oscillators or high-pulse-energy gas lasers in the infrared to excite vibrational transitions in molecules, and use infrared cameras to image vibrational infrared fluorescence. These techniques have been demonstrated in flows ranging from mom-temperature mixing to laminar diffusion flames.
- Lasers and Masers
- Combustion and Ignition