Molecular Dynamics Method for Micro/Nano Systems
Molecular Dynamics Method for Micro/Nano Systems
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DOI：
10.1002/9780470172599.ch21
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发表时间：
2009-01
期刊：
影响因子：
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通讯作者：
S. Maruyama
中科院分区：
文献类型：
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作者：
S. Maruyama
分子动力学模拟对于微尺度和纳米尺度的传热问题变得越来越重要和实用。例如，对相变等传热基本机制的研究需要了解微观的液-固接触现象。三相界面（液体在固体表面上的蒸发和冷凝）的有效传热成为宏观处理中的奇异问题。蒸汽中液滴或液体中汽泡的成核理论有时需要考虑分子团簇大小的核。表面活性剂对液-气界面传热传质的影响也是分子尺度现象对宏观传热传质直接影响的一个例子。尽管已经有很多努力将我们的宏观分析扩展到空间（微米和纳米尺度），时间（微秒，纳秒和皮秒）和速率（极高的热通量）中的极微观条件，但外推仍有一定的局限性。因此，强烈期待从分子水平的自下而上的方法。另一方面，在微米和纳米尺度的传热和纳米技术的最新进展需要在纳米和微米尺度制度的相变和传热传质的详细了解。产生纳米级结构如碳纳米管或中孔二氧化硅结构的化学工程过程就是例子。液体的润湿或吸收也是重要的，因为粘附力对于微米/纳米系统是极其重要的，并且利用纳米级结构可以产生极大的表面积。分子动力学模拟的使用对于这样的纳米级系统是直接的。在这里，将这种纳米现象与宏观现象进行比较是很重要的，因为对宏观系统的类比通常是理解纳米现象的重要策略。纳米尺度系统所固有的重要物理特性通常是通过与宏观系统的理性比较而发现的。在这一章中，有前途的数值技术之一，经典的分子动力学方法，概述了特别强调的应用程序相间和传热问题。分子动力学方法作为统计力学和物理化学的工具已经使用很长时间并得到很好的发展[1，2]。然而，将该方法扩展到宏观传热现象的空间和时间尺度是一个新的挑战[3-6]。另一方面，与薄膜技术相关的…
Molecular dynamics simulations are becoming more important and more practical for microscale and nanoscale heat transfer problems. For example, studies of basic mechanisms of heat transfer such as phase change demand the understanding of microscopic liquid-solid contact phenomena. The efficient heat transfer at a three-phase interface (evaporation and condensation of liquid on a solid surface) becomes the singular problem in the macroscopic treatment. The nucleation theory of liquid droplets in vapor or of vapor bubbles in liquid sometimes needs to take account of nuclei of the size of molecular clusters. The effect of the surfactant on the heat and mass transfer through liquid-vapor interface is also an example of the direct effect of molecular scale phenomena on the macroscopic heat and mass transfer. Even though there has been much effort of extending our macroscopic analysis to extremely microscopic conditions in space (micrometer and nanometer scales), time (microseconds, nanoseconds and picoseconds), and rate (extremely high heat flux), there are certain limitations in the extrapolations. Hence, the bottom-up approach from molecular level is strongly anticipated. On the other hand, recent advances in microscale and nanoscale heat transfer and in nanotechnology require the detailed understandings of phase change and heat and mass transfer in nanometer and micrometer scale regimes. The chemical engineering processes to generate nanoscale structures such as carbon nanotubes or mesoporous silica structures are examples. The wetting of liquid or absorption is also important since the adhesive force is extremely important for micro/nano system and the creation of extremely large surface area is possible with nanoscale structures. The use of molecular dynamics simulations is straightforward for such a nanoscale system. Here, again, it is important to compare such nanoscale phenomena with macroscopic phenomena, because an analogy to the macroscopic system is often an important strategy in understanding a nanoscale phenomenon. Important physics intrinsic to a nanoscale system is usually found through the rational comparison 4 with a macroscopic system. In this chapter, one of the promising numerical techniques, the classical molecular dynamics method, is overviewed with a special emphasis on applications to inter-phase and heat transfer problems. The molecular dynamics methods have long been used and are well developed as a tool in statistical mechanics and physical chemistry [1, 2]. However, it is a new challenge to extend the method to the spatial and temporal scales of macroscopic heat transfer phenomena [3-6]. On the other hand, the thin film technology related …