Experimental Investigation of Suspended Water, Ethanol and Acetone Droplets Transient Phase Change Regimes in the Heated Airflow

Abstract

This paper presents an experimental investigation into the use of water, ethanol, and acetone using the suspended droplet method. The influence of atmospheric air temperatures on droplets in the transient phase change is analysed. Experimental results are presented, including thermograms that characterise the droplet's thermal state and diameter monograms that define the variation in droplet size. These data are processed according to the droplet liquid volume change rate parameter. The experimental results confirm that the airflow temperature leads to intensified heat exchange and phase change processes during the droplet transition stages, resulting in the droplet's heating to a higher thermal equilibrium evaporation state. For all the fluids studied, the impact of airflow temperature on the droplet temperature and liquid volume change rate of different liquids is qualitatively similar. Still, the strength of the influence varies depending on the nature and properties of the liquid. In heated air up to 50 °C, the droplet equilibrium temperatures are approximately 8.5 °C for acetone, 22.2 °C for ethanol and 28.3 °C for water. In 100 °C air, these values become approximately 17.8 °C, 32.3 °C and 43.4 °C, respectively. The estimated volume change in the liquid droplet's size shows that acetone, which has the most volatile properties and lowest boiling temperature, evaporates most intensely from the liquids tested in the initial stage.