Molecular Dynamics Simulation Of Transport Behavior Of Argon Confined In Micropore Driven By Temperature Gradient

Nanoparticles may be driven by electrophoresis, osmosis, gradients in the surface tension, pressure gradients, and thermophoresis in nanochannels. The use of temperature gradients to induce mass transport is known as thermophoresis, the Soret effect, or thermodiffusion. It provides a new thought for studying nanoscale manipulators. The realization of an efficient transport technique may motivate us to explore its use for nanoscale pumping devices, drug delivery by nanosyringes and so on. The law of the flowing in nanoscale plays an important role in the design and optimization of nano-fluid devices. Carbon nanotubes (CNTs), featuring unique structure and amazing properties, have potential applications in nano-electro-mechanical system (NEMS). They could serve as ideal nanoscale model in studying all kinds of properties of the nanoparticles in nanoscale. Recently, nanoparticles confined in CNT have been considered in numerous studies. The molecular simulation. overcoming the particularity of the size of the nanodevice, has become a powerful research tool in addition to the experiment. We can observe microscopic details and the comprehensive effect of various influence factors at the molecular scale by it.In this thesis molecular dynamics (MD) simulation was performed to investigate the transport behavior of Argon confined in slit pore and SWNT driven by temperature gradient. In slit pore, the methods of constant heat flux and constant temperature gradient were used to set temperature gradient, and the results were compared. In SWNT, a systematic study of the influence on the dynamic and structure distribution of Argon was carried out. The effects of temperature gradient, density of Argon, radius of SWNT and average temperature on the dynamic and structure properties of Argon were discussed.1. When the method of constant heat flux is used, Argon has the same diffusion behavior in x, y, z direction. However, it keeps invariable with the increasing of temperature gradient. When the method of a constant temperature gradient is used, the center of mass of Argon migrated to the cold end and oscillated reaching a steady stage. Percent distribution of Argon presents non-homogeneous distribution along the z axis. Argon has the same diffusion behavior in x, y direction, which is larger than that in z direction.2. The competition between temperature gradient and concentration gradient causes the unusual behavior of fluid in S WNT.3. In dynamic aspect, the value of the maximum velocity of Argon is in proportion to temperature gradient. However, it decreases with the increase of density of Argon. If the average temperature is low enough, the velocity behaves specific due to the molecular clusters and vacuum areas appear in SWNT.4. In structure distribution aspect, strong inhomogeneous distribution becomes more obvious with increasing the temperature gradient or decreasing the density of Argon and average temperature. However, the radius of SWNT has a weak effect on both of them compared with other influencing factors.