THERMOMETRY OF FLOW FIELDS USING A TWO-COLOR RATIOMETRIC PLIF TECHNIQUE

In this paper, a two-color ratiometric planar laser-induced fluorescence (PLIF) technique for the measurement of temperature fields of liquids is described. The method uses the temperature sensitive rhodamine B and temperature insensitive rhodamine 110 fluorescent dyes. The ratio of the fluorescent emission intensity of these two dyes is inversely proportional to temperature and is independent of laser intensity variation in the flow field. Because the emission spectra of these two dyes overlap, a correction was developed to disentangle the two signals. In addition, the absorption and emission spectrums of rhodamine 110 overlap, leading to the self-attenuation of the fluorescent signal by the dye. A correction with respect to path length was developed for self-attenuation. The paper presents calibration information and visualization of temperature gradients in a glass water tank with motion induced by large temperature gradients.