Drop impact on solid surfaces, aside from its inherent beauty, plays an important role in industrial processes as diverse as ink-jet printing, spray cooling, and spray coating. The impacting drop deforms before making contact with the target surface, and an air layer is formed between the droplet base and the solid surface. Using high-speed color interferometry, we study the dynamics of the air layer, the wetting mechanism and bubble entrapment. When a liquid droplet impacts on a surface heated above the liquid's boiling point, the droplet either immediately boils when it contacts the surfaces (contact boiling), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (film boiling). We investigate how the boiling dynamics of the impacting droplet change with impact inertia and substrate properties.

 

Prof. Chao Sun obtained his PhD from the Chinese University of Hong Kong in 2006, and received the Hong Kong Young Scientist Award in the same year. Afterward, he did one-year postdoc in Chinese University of Hong Kong and one-year postdoc at University of Twente in the Netherlands. In 2009 he was appointed as an Assistant Professor at Applied Physics Department in University of Twente. He was promoted to a tenured Associate Professor in 2013. In 2015, he joins the Center of Combustion Energy and Department of Thermal Engineering at Tsinghua University as a professor. He has published more than 70 journal papers including Annu. Rev. Fluid Mech., J. Fluid Mech., Phys. Rev. Lett., Nature Commun. His research interests include High-Reynolds number turbulence, bubbles and droplets, multiphase flows, heat and mass transfer, and microfluidics.