THERMOPHYSICAL PROPERTIES AND BOILING HEAT TRANSFER OF SELF-ASSEMBLED NANOEMULSION FLUIDS

Abstract

Recently, society has witnessed a blossom of the development of electronics, communications, and auto-computing industries, and this trend is going to continue through this century. The power dissipation density has been increased drastically because of the continuous miniaturization and the multiplication of speed of operation and data transfer. Today, it is not unusual to see heat fluxes of 200 W/cm2 in a power module, a figure that is expected to increase up to 1000 W/cm2 in the near future. Thermal management of such high flux is quickly becoming the bottleneck to improvements in electronic and optoelectrical devices. Most efforts to improve thermal management technology in the past has been devoted to improving transport processes, such as jet impingement, and microchannels. Much less attention has been paid to the fact that the existing fluids themselves possess poor thermal transport properties.

In this study, Nanoemulsion fluids have been developed to overcome barriers of state-of-the-art heat transfer fluids via forming self-assembled liquid nanodroplets in conventional heat transfer fluids to elevate their heat transfer capability. A systematic investigation on nanoemulsion fluids especially their applicability in thermal management of high heat flux devices was done on the following topics: (a) the preparation of several nanoemulsion heat transfer fluids and their inner structure characterization; (b) investigation of thermophysical and phase change heat transfer characteristics in both pool boiling and flow boiling conditions; (c) optimization of nanoemulsion fluids for better thermal performance and to identify the influence of different dispersed phase, base fluid and surfactants and their concentration, on (1) inner structure and thermophysical properties, and (2) on the phase change heat transfer characteristics; (d) analytical/numerical modeling and simulation of the nanoemulsion fluids and their enhanced thermophysical properties.

Overall, nanoemulsion fluids with greatly enhanced heat transfer properties, especially, the phase change properties has been developed and demonstrated here. Potential applications and the future of nanoemulsion fluids are discussed too