LAUSR

Abstract Over the recent years, the research community has taken an increasing interest in high-temperature gas-steam-droplet systems. This promotes emerging technologies in thermal or flame water cleaning from unspecified impurities, and firefighting by water slurry aerosols. Unfortunately, these technologies have yet to become mainstream, although they have been regarded as extremely important and promising for several years already. The fact is that there are too few experimental data on the physical processes intensifying the evaporation of water slurries in hot gaseous media. The results of such experiments with temperatures over 1000 °C are virtually impossible to find. These data are so evasive due to fast-paced processes and difficulties in measuring the temperature in evaporating heterogeneous water droplets. The typical durations of high-temperature heating and evaporation do not usually exceed several seconds. In this work, we conduct experiments using a heterogeneous water droplet with a single nontransparent solid inclusion to determine the unsteady temperature field of the latter. We use an optical diagnostic technique, Planar Laser Induced Fluorescence, to study the conditions, mechanism, reasons and characteristics of water boiling leading to an explosive breakup (disintegration) of water slurry droplets. Rhodamine B acts as a fluorophore. The typical temperatures are determined in the depth of a droplet, near its free (outer) surface, and at the interface. The water temperature at the water – solid inclusion interface is shown to be higher than at the outer surface of a droplet. Furthermore, we compare the temperature fields of a homogeneous and heterogeneous water droplet under identical heating conditions.