Thermal Transport in Micro- and Nanoscale Systems

Abstract

Small scale (micro/nanoscale) heat transfer has broad and exciting range of applications. Heat transfer at small scale quite naturally is influenced-sometimes dramatically-with high surface area to volume ratios. This in effect means that heat transfer in small scale devices and systems is influenced by surface treatment and surface morphology. Importantly, interfacial dynamic effects are at least non-negligible and there is a strong potential to engineer the performance of such devices using the progress in micro and nanomanufacturing technologies. With this motivation, the emphasis here is on heat conduction and convection. The chapter starts with a broad introduction to Boltzmann Transport equation which can capture the physics of small scale heat transport and outlining the reasons why small scale transport distinct from classical micro scale heat transport. Among applications, examples are thermoelectric and thermal interface materials where micro and nanofabrication has led to impressive figure of merits and thermal management performance. Basic of phonon transport and its manipulation through nanostructuring materials are discussed in detail. Small scale single phase convection and the crucial role it has played in developing the thermal management solutions for next generation of electronics and energy harvesting devices are discussed as next topic. Features of micro cooling platforms and physics of optimized thermal transport using micro channel manifold heat sinks are discussed in detail along with a discussion of how such systems also facilitate use of low grade, waste heat from data centres and photovoltaic modules. Phase changes process and their control using surface micro/nanostructure are discussed next. Among the feature considered, the first are microscale heat pipes where capillary effects play an important role. Next the role of nanostructures in controlling nucleation and mobility in boiling, condensation and icing are discussed great detail. Special emphasis is placed on the limitations of current surface and device manufacture technologies while also