Single Shot Temperature Measurements using Coherent Anti-Stokes Raman Scattering in Mach 14 Flow at the Hypervelocity AEDC Tunnel 9
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© 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy is used as a non-intrusive optical diagnostic technique to obtain time-resolved temperature and density measurements in high enthalpy gas flows. A femtosecond hybrid CARS system provides single shot vibrational and rotational CARS spectra of nitrogen molecules at 1kHz in low-density hypersonic flow. The system performance for temperature and density measurements has been evaluated in Mach 14 freestream nitrogen flow at the AEDC Hypervelocity Wind Tunnel 9. Measurements of translational/rotational temperature, Trot, and vibrational temperature, Tvib, are obtained by fitting the experimental CARS spectra obtained in freestream hypersonic flow to theoretical nitrogen spectra. The results experimentally demonstrate, for the first time at Tunnel 9, the strong thermo-chemical non-equilibrium conditions of the flow, with Tvib ~ 1300K and Trot ~ 50-60K.
author list (cited authors)
Dogariu, A., Dogariu, L. E., Smith, M. S., Lafferty, J., & Miles, R. B.