Micro-Scale Laser-Induced Fluorescence Thermometry For Multiphase Flow Of Immiscible Liquids

In this work an implementation of laser induced fluorescence thermometry technique at the micro-scale for application in multiphase flow of two immiscible liquid is presented. The selected fluid phases are water and n-decane. One key limiting factor for dye selection is that each dye must be soluble in only one of the liquid phases. The selected fluorescent dyes are sulforhodamine 101 (SR) and eosin Y (EY) in water, and pyrromethene 597-8C9 in n-decane. The technique uses ratiometric two-color two-dye approach for water and two-color one-dye approach for n-decane. The two imaging wavelength bands are 540–572 nm and 610–640 nm. The technique yields a measurement sensitivity of 1.7% "K" ^"-1" in water and ~0.1% "K" ^"-1" in n-decane in the temperature range 20–60 ºC with a spatial and temporal resolution of 5.2 µm and 1 s, respectively. The sensitivity and uncertainty level achieved herein are satisfactory and near expected values for the aqueous phase. For the non-aqueous phase, modifications in the optical setup and/or choice of fluorescent dye(s) are needed to improve the sensitivity of the measurement technique.