| Summary: | 碩士 === 國立交通大學 === 機械工程系所 === 93 === This study discusses microscale heat transfer phenomena in two dimensional nanostructures based on the microscopic heat transport theory. The phonon Boltzmann equation model is established to analyze the effects of the wire size on the thermal conductivity of nanocomposites of nanowires embedded in a host semiconductor material and nano porous silicon wire. First, we predict the thermal conductivity of the arranged in align and stagger rows nanocomposites of nanowires. The Inelastic diffuse mismatch model is utilized to simulate the phonon transfer across the interface between two different materials and the results show that the negligible sensitivity of thermal conductivity to wire arrangement. Second, we present the numerical analysis on estimating the thermal conductivity of nano porous silicon wire. It shows that the size between the pores affects the probability of the phonon collide with the pores boundary in align model. In stagger model, phonon will be blocked up the path through the wire. It also means that the larger size of the pores, the lower thermal conductivity of the wire. The results of this study can be used to direct the development of high efficiency thermoelectric materials.
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