A study of interface evolution-triggering different nucleate boiling heat transfer phenomenon on the structured surfaces

Abstract

As the main factor limiting the performance of microprocessors, how to improve its heat dissipation capacity is critical. Nucleate boiling on the structured surface is a method that can improve heat transfer significantly due to two-phase flow, and bubble behaviors have been attracted much attention because of its capability of enhancement on critical heat flux(CHF). Although a large number of studies have proved that the structured surface can improve CHF by increasing the number of nucleation sites, bubble departure frequency and reducing bubble departure radius, the mechanism of solid-liquid-gas interface evolution on the structured surface is still unclear, which has significant effects on nucleate boiling. Therefore, a model of nucleate boiling of liquid on the structured surface was constructed, the processes of nucleate generated and bubble growth were observed directly by using molecular dynamics simulation. A novel phenomenon was observed in which the position and number of interfaces are mainly dependent on the restriction of potential energy generated by structures. This phenomenon affects CHF significantly due to the area of the microlayer beneath the bubble was different. In addition, the effects of liquid retention on interface and CHF were also explored, the result showed that CHF increased with the increase of liquid retention, and the increase rate of CHF was slowed down due to the more retained liquid in the structures. We believe that this research can improve the existent theory of nucleate boiling and provide a more effective theoretical basis for the design, processing and application of surface with the nanostructure.