Contact line region heat transfer mechanisms for an evaporating interface

• A critical evaluation of the forces acting in the contact line region is presented.
• Importance of microlayer and microconvection in contact line region is highlighted.
• Optical and thermal measurement techniques used in contact line region are presented.
• Contribution of various modes of heat transfer in contact line region during boiling.

Many recent studies have emphasized the significance of contact line region heat transfer in applications such as boiling, thin film evaporation and enhanced heat transfer using wicking structures. Literature on heat transfer in the contact line region have focused on the adsorbed layer and transition region of the contact line. However, the region beyond the thin film region of the contact line plays a significant role in heat transfer and associated phase change at the dynamic interface. In this paper, heat transfer in the adsorbed and transition regions as well as in the macro region is reviewed. The need for studying the microconvective effects for polar liquids because of their broad practical application in boiling is also highlighted. Experimental and analytical works on the contact line region are explored and a comprehensive picture of its physical and heat transfer characteristics is presented. Various optical and thermal measurement techniques employed by researchers to understand evaporation in the contact line region are also reviewed. Finally, the contribution of the various modes of heat transfer within the contact line region during nucleate pool boiling is discussed and future research needs are identified.