A two-dimensional Raman technique was used to investigate mixing phenomena of cryogenic jets under both supercritical and transcritical conditions. The aim of this study was to enlarge the experimental data basis for modeling purposes and to provide quantitative information to help to improve the design of injectors for high-pressure rocket engine combustion chambers. Cryogenic nitrogen, which served as substitute for liquid O2, was injected into N2 at room temperature at pressures up to 6.0 MPa. The liquid N2 jet could be atomized by a coaxial H2 flow. Raman scattering was generated with a XeF excimer laser. The resulting signal images were discriminated against background by spectral filtering and preferential detection of light with a polarization corresponding to the polarization of the laser, thus making use of the conserved polarization of the Raman-scattered light. The Raman images were converted into density distributions of N2 and H2, respectively, as well as into temperature distributions for a variety of experimental conditions.
© 1998 Optical Society of America
(280.2490) Remote sensing and sensors : Flow diagnostics
(290.5860) Scattering : Scattering, Raman
(300.6250) Spectroscopy : Spectroscopy, condensed matter
(300.6450) Spectroscopy : Spectroscopy, Raman
Michael Decker, Axel Schik, Ulrich E. Meier, and Winfried Stricker, "Quantitative Raman Imaging Investigations of Mixing Phenomena in High-Pressure Cryogenic Jets," Appl. Opt. 37, 5620-5627 (1998)