Dynamic characteristics of droplet impact on a cold cylindrical surface

Abstract

The freezing phenomenon often leads to economic and safety losses in various industries. Studying the processes of droplets impact on cold surfaces is beneficial in preventing potential harm. In this study, the processes of droplet impact on a cold cylindrical surface are investigated by high-speed photography. How the dynamic characteristics are affected by Weber number and surface temperature are studied. The results indicate that when the surface temperature is between −25 to −5 °C, an increase in Weber number results in higher initial kinetic energy and greater viscous dissipation. During the spreading process, the initial kinetic energy predominates, leading to an increase in the maximum spreading ratio. However, the rise in viscous dissipation contributes to an increase in the stable ratio. As Weber number increases, both the maximum spreading time and stable time decrease. Over the same range of surface temperatures, a decrease in surface temperature results in increased viscous dissipation, which leads to a reduction in the maximum spreading ratio. The maximum spreading time and stable time, however, are not significantly affected by surface temperature. Moreover, the relationships of the maximum spreading ratios and stable ratios between axial and circumferential directions are constructed respectively. These relationships exhibit similar linear characteristics, which are not affected by the Weber number and surface temperature.