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

ABSTRACT

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.

KEYWORDS:

• Droplet evaporation
• contact angle
• heat and mass transfer
• experiment
• numerical simulation

Additional information

Funding

This work was supported by the Fundamental Research Funds for the Central Universities in China; National Natural Science Foundation of China [51876067,51936005]; Natural Science Foundation of Guangdong Province [2018B030306014].