Manipulating Bubble Dynamics and Heat Transfer using 3D Superbiphilic Micro/Nanostructures

With the development and miniaturization of high density integrated circuits and multi-functions of electronic chips, the heat flux generated by the chips has been greatly increased, which becomes a bottleneck for further development. Therefore, it is emergent to develop new and efficient thermal management techniques for electronics cooling. Phase change heat transfer, such as boiling and evaporation, is a promising technique for the cooling of electronic devices. However, the prevention of vapor film formation is a fundamental challenge for the enhancement of phase change systems, and an impetus therefore exists for the discovery of new techniques to segregate nucleation during their formation. It has been shown that the surface of the three-dimensional superbiphilic wettability patterns can control the bubble dynamics and phase transition process of the three-phase contact line, thereby greatly enhancing the heat transfer coefficient and critical heat flux of pool boiling and flow boiling with a range of geometries, orientations and morphologies in order to influence the surface-tension forces which resist the bubble’s departure and wicking performance. Previous study also found that the concentration Marangoni effect using low-boiling-point multi-component working fluids may help further improve heat transfer performance. Therefore, it is of great interests to study the multiphase flow, wicking performance, heat and mass transfer and contact line dynamics on the three-dimensional superbiphilic wettability patterned surfaces. This talk will present our recently progresses in novel three-dimensional superbiphilic wettability patterns for enhancing phase change heat transfer and how to manipulate the liquid propagation coefficient using non-uniform micropillar array. The experimental results utilizing high speed visualization and timeresolved PIV systems will be presented.