TEMPERATURE-MEASUREMENTS IN GASES BY USE OF PLANAR LASER-INDUCED FLUORESCENCE IMAGING OF NO

Two techniques based on planar laser-induced fluorescence of NO are ap plied to the measurement of two-dimensional temperature fields in gase ous flows. In the single-line technique, the NO fluorescence signal, w hich is in general a function of temperature, pressure, and mole fract ion, can be reduced to a function of temperature alone. In this limit, a single measurement of fluorescence can be directly related to tempe rature, In contrast, in the two-line thermometry technique the ratio o f fluorescence signals resulting from excitation of two different rovi bronic states is related to the fractional populations in the initial states, which are solely a function of temperature. The one-line metho d is applied to the study of a laminar heated jet, and the two-line te chnique is used to measure temperature in a supersonic underexpanded j et. In addition, energy transfer in NO laser-induced fluorescence is a nalyzed with multilevel rate equation models. Finally, an accurate mod el is developed for prediction of the temperature dependence of the NO fluorescence signal.