ABSTRACT This paper is aimed at describing the impact and evaporation of a water droplet onto smooth horizontal aluminium surfaces, at temperature between 110°C and 160°C. An experimental set-up has been designed and realized, it consists of a droplet generation system, an electric heater, an aluminium plate, a temperature and images acquisition system. The research has been carried out by an infrared video camera and a high-speed CCD camera characterized by a frame-rate of 955 fps. Images and measures have been recorded for different values of wall temperatures and Weber numbers. The generation system provides identical drops of 14.14 µl (3 mm diameter). A short theoretical investigation is presented, to introduce the dynamic and thermodynamic features. The image processing allows to determine the temperature distribution during the droplet spreading after impact, the droplet shape before complete evaporation, the wetted solid surface diameter, the complete evaporation time (or resident time), the removed heat flux and the average heat transfer coefficient between drop and aluminium surface. The resulting database provides a contribute and a further insight into the complex phenomenon of drop impingement and evaporation on hot surfaces.
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