High-temperature (over 500 K) evaporation of water, emulsions, slurries and solutions has been extensively studied over the recent years due to a number of prospective applications. Some of these are, for example, the evaporation or burnout of impurities in the course of for thermal wastewater treatment, gasification, as well as flue gas waste heat recovery by intermixing them with water and water vapor to create a new generation of heat transfer agents. Further development of these technologies is constrained by the fact that the approaches used so far are mostly empirical. Obtaining reliable experimental data on evaporation characteristics (vaporization rate and lifetime) of water emulsion droplets in the course of thermal evaporation and burnout of impurities is a pressing task. It is also desirable to experimentally cover all the temperature ranges, droplet sizes, and component concentrations, typical of advanced water treatment. In this research, we use high-speed hardware-and-software system to track the free surface of a droplet. We determine the dependence of heating and complete evaporation time as well as heating and vaporization rate on the gas environment temperature, droplet size, and emulsion component concentration. We then derive the approximating equations for the dependences determined. The difference in evaporation conditions and characteristics is also defined for droplets of water and emulsions with different additive types and concentrations. Finally, we outline different modes of evaporation as well as the required conditions for monotonous evaporation or explosive breakup (pulverization).
|Журнал||International Journal of Heat and Mass Transfer|
|Состояние||Опубликовано - 1 ноя 2018|
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes