本文運用分子動力學模擬研究奈米粒子的熱物性與尺寸關係，並結合平行計算技巧探討奈米粒子懸浮流體的結構特性與傳輸性質。在奈米粒子模擬方面，所探討的物理性質包含內聚能、表面能、均方根位移(RMSD)、熔化溫度及熱傳導係數等；在奈米粒子懸浮流體模擬方面，所探討的製備參數包含粒子尺寸、粒子體積分率及溫度等。由奈米粒子的熱物理性質模擬結果可得，當矽奈米粒子的原子數目(N)大於357個時，粒子的熔化溫度與尺寸(N-1/3)呈線性關係，在原子數目為N=281與N=191模擬結果中，粒子的熔化溫度高於此線性關係預測的數值；矽奈米粒子在熔化溫度時的尺寸小於固態時的尺寸；矽奈米粒子的內聚能與尺寸(1/d，其中d為粒子的直徑)呈線性關係，且與溫度無關；小尺寸的矽奈米粒子具有較顯著的結構重組行為，較容易產生晶格缺陷；矽奈米粒子的熱傳導係數低於塊材數值約2個量級，且隨著溫度增加有明顯下降的趨勢。由奈米粒子懸浮流體的結構特性與傳輸性質模擬結果可得，液體會在固體粒子的表面附近形成有序結構殼層，並隨著粒子尺寸減小而變得更顯著；當粒子體積分率增加時，奈米粒子於流體中的懸浮穩定性亦隨之增加；當富勒烯(fullerene)碳球加入液態水中，水分子的擴散係數與富勒烯碳球加入量呈線性關係，與富勒烯碳球的尺寸無關；在非常微量的粒子加入基質流體中，對流體的黏滯係數增量效應有顯著增加趨勢，尤其在低溫的條件中更明顯；奈米粒子懸浮流體由模擬得到的熱傳導增量大於理論模型預測數值約1個量級；奈米粒子懸浮流體的熱傳導增量大致上可歸因於懸浮奈米粒子本身的熱傳特性及固液界面處形成有序結構，而改變固體粒子與液態流體間的熱阻。最後，我們提出一些分子動力學模擬的改進方法及奈米粒子的其他應用，作為今後研究的方向。

This study investigates the thermophysical properties of nanoparticles with various sizes and the structural features and transport properties of nanoparticles suspensions using molecular dynamics simulations with parallel computing technique. The physical properties of nanoparticle in the simulation are including cohesive energy, surface energy, root mean square displacement (RMSD), melting temperature, and thermal conductivity. The composed parameters of nanoparticles suspensions in the simulation contain particle size, particle volume fraction, and temperature. From the simulated results about the thermophysical properties of nanoparticles, there exists a linear relation for the silicon nanoparticles with more than 357 atoms, within which the melting temperature of particle varies inversely as N-1/3, and the melting temperatures for particles with N=281 and 191 are both seen to be higher than the values predicted from linear fitting; the size of the silicon nanoparticle when it approaches its melting temperature is less than when it is in a solid state; the silicon nanoparticle cohesive energy can be fitted to a linear function of 1/d, where d is the particle diameter, and is independent of temperature; the small particle has a heavily reconstructed geometry, which easily generates lattice imperfections; the calculated thermal conductivities of the silicon nanoparticles are lower than that of the bulk by approximately two orders of magnitude, and decreases rapidly as the temperature increases. From the simulated results of the structural features and transport properties of nanoparticles suspensions, an organized structure shell of liquid is formed close to the surface of solid particle and the shell structure formation becomes more pronounced as the particle size is reduced; the suspension stability of nanoparticles is improved as the particle volume fraction is increased; the diffusion coefficient of the water molecules in fullerenes-in-water suspensions varies as a linear function of the fullerene loading, but is independent of the fullerene size; the dispersion of even a very small amount of particles in the base fluid leads to a significant increase in the viscosity enhancement effect, which is more pronounced at a lower temperature; the simulation results for the thermal conductivity enhancement of nanoparticles suspensions are approximately one order of magnitude higher than the predictions from the theoretical modes; the enhanced thermal conductivity of nanoparticles suspensions is most likely attributed to the nature of heat conduction in nanoparticles and an organized structure at the solid/liquid interface, thereby changing the barrier to heat flow between the solid particle and the liquid fluid. Finally, we present several improvement ways of molecular dynamics simulations, and other application of nanoparticles as our future works.

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