Experimental investigations into the high-temperature (700 to 1200 K) heating, evaporation, ebullition, and subsequent disintegration (breakup) of droplets of water emulsions (with a volume concentration of petroleum products to 70%) have been performed using high-speed video recording. Consideration has been given to the emulsions based on water, oil, mazut, kerosene, and industrial oil. A study has been made of two schemes of supply of energy to the droplet: local heating due to the contact with a heated metallic rod with variation in the cross section of its tip and evaporation on a massive heated substrate, i.e., a steel platelet of diameter 50 mm and thickness 5 mm. From the results of an analysis of the frames of videograms illustrating different schemes of implementation of the investigated processes of transformation of the surface of the emulsion droplet and of its heating, evaporation, filling with vapor bubbles, ebullition, and breakup, the authors have established the influence of basic factors (temperature and surface area of heating, concentration of the components, droplet dimensions, and properties of petroleum products) on the time of full evaporation of the emulsion droplet. Distinctive features of the processes of evaporation and ebullition of emulsion droplets in high-temperature superheating have been determined. The authors have singled out different regimes of heating of the droplets, which differ not only by the time of full evaporation but also by the effects (preservation of a monolithic state, explosive disintegration accompanied by the formation of a fine aerosol, and ignition of the emulsion).
ASJC Scopus subject areas
- Condensed Matter Physics