Instantaneous measurement of two-dimensional temperature distributions by means of two-color planar laser induced fluorescence (PLIF)

We present a noninvasive technique to measure instantaneously two-dimensional temperature distributions in liquid flows by means of two-color planar laser induced fluorescence (PLIF) of rhodamine B. This technique allows absolute temperature measurements by determining the relative intensities on two adequate spectral bands of the same dye and a reference measurement at a known temperature. Demonstration measurements on a heated turbulent jet injected into a coflow at ambient temperature are presented. The mean temperature field is investigated, as well as the temperature fluctuations. The results are compared to those obtained by means of a usual single-color PLIF technique.