Droplet impacting dynamics: Recent progress and future aspects

Droplet impact behaviours are widely applied in a variety of domains including self-cleaning, painting and coating, corrosion of turbine blades and aircraft, separation and oil repellency, anti-icing, heat transfer and droplet electricity generation, etc. The wetting behaviours and impact dynamics of droplets on solid and liquid surfaces involve complex solid-liquid and liquid-liquid interfacial interactions. The modulation of droplet dynamics by means of specific surface morphology and hydrophobic/hydrophilic patterns, which in turn can be derived to related applications, is one of the current promising interests in the interfacial effect modulating droplet dynamics. This review provides a detailed overview of several scientific aspects of droplet impact behaviours and heat transfer processes influenced by multiple factors. Firstly, the essential wetting theory and the fundamental parameters of impinging droplets are introduced. Secondly, the effects of different parameters on the dynamic behaviours and heat transfer of impinging droplet are discussed. Finally, the potential applications are listed. Existing concerns and challenges are summarized and future perspectives are provided to address poorly understood and conflicting issues.