Two-Phase Flow and Heat Transfer in Micro-Channels and Their Applications in Micro-System Cooling

Heat management in high thermal-density systems is confronting rising challenges due to the extremely high heat dissipation capacity requirement in ever more miniaturized and intensified processes. Efforts have been made for heat transfer enhancement. A number of heat transfer technologies including natural convention and radiation, forced convection, pool boiling, micro-channel flow boiling, heat pipes and capillary pumps were introduced. However, the drastically increasing heat transfer requirements are still calling for extensive experimental investigations, especially on the phase change processes in micro-scale. A review of the experimental studies on two-phase flow boiling and heat transfer in small flow passages was presented. Some experimental results published in the year 1993–2010 were overviewed, revealing some controversial conclusions on micro-scale flow boiling heat transfer mechanisms. Besides, several existing heat transfer correlations were assessed. It should be admitted that the existing database is still limited, especially for flow boiling in passages with unique geometries such as high-aspect-ratio cross section. Extensive explorations on two-phase flow boiling and heat transfer in micro-channels are essential for heat transfer predictions and applications in micro-systems.