Abstract
Droplet impacts on solid wall are key elements in technical applications, such as rapid spray cooling, ink-jet printing and semiconductor cleaning. There exist varieties of physical parameters proposed that control the droplet impact although they are not thoroughly explored; hence, dynamics of the droplet after the impact are yet fully understood. After droplet impacts on solid wall, characteristic flows called lamella and splash occur. We examine the effects of the surrounding gas on droplet impacts by observing these flows. In this study, We experimentally observed the high-temperature droplet impact on smooth surface in a vacuum chamber with a high-speed photography, in order to clarify the effects of the temperature of the surrounding gas. The results show that the splash can be suppressed by increasing the temperature of the surrounding gas. We examined splash threshold proposed by Wal et al. to find that this splash threshold cannot be applicable at high temperature.
