Experimental and numerical research of liquid contact angles on solid surfaces under evaporation conditions: a review

The liquid contact angle on a solid surface is important in evaporation processes, which characterizes the wettability, and the spread of liquid films or droplets on the working surface. Thus, it critically affects heat and mass transfer, and evaporation performance accordingly. The evaporating droplet contact angle is complicated, accompanied by internal flow, heat/mass transfer, and phase change, and has received considerable attention in recent years. This paper summarizes the recent research progress of the measurement and simulation methods for determining the liquid contact angles of evaporation processes, including experimental approaches such as the sessile droplet, Wilhelmy and inclined plate methods, as well as numerical approaches such as the molecular dynamics, computational fluid dynamics, and lattice Boltzmann methods. The principles, applicable conditions, and limitations of these methods are analyzed and compared. This paper also discusses the measurement methods and effects of influencing factors related to the evaporating droplet contact angle, such as temperature and velocity distribution. Besides, it is discussed to enhance liquid evaporation by changing the droplet contact angle. Finally, a brief summary and suggestions for future work are presented.

Automated summary

The liquid contact angle on a solid surface plays a critical role in evaporation processes, affecting wettability, liquid film/droplet spreading, and heat and mass transfer. Recent research has focused on the complex evaporating droplet contact angle, with advancements in measurement and simulation methods. Various experimental and numerical approaches have been used, analyzing the principles, applicable conditions, limitations, and factors influencing contact angle. Discussions also involve enhancing evaporation efficiency by modifying the droplet contact angle, with a brief summary and suggestions for future work presented.