The Molecular Dynamics Simulation Of Microscale Thermal Phenomena Of Interface

Regarding with Lennard-Jones fluid argon, some microscale thermal phenomena were studied with molecular dynamic simulation in this paper. The distributions of the local density, thickness, temperature, tangential and normal stress and surface tension were acquired by the study of liquid-vapor interface. These simulated data agree well with corresponding experimental data and the MD simulation results from other authors, consequently it is proved that the model and simulation method in the paper are correct. Furthermore, different initial conditions show effect on these parameters. The fractal theory was used to study the character of liquid-vapor interface in the paper, hence the application of the fractal theory in thermal subjects could be solved and a way to calculate the fractional dimension number in the process of simulation could be put forward. The fractional dimension number describing the character of the liquid-vapor interface was calculated. The distinct fractional dimension numbers in X, Y and Z direction reveal that the simulation system is an anisotropic one. It is concluded that the liquid-vapor interface is a typical fractal surface by the qualitative and quantitative analysis for liquid-vapor interface. On the other hand, the influence of the solid wall on the saturation thermodynamic parameter of argon under microscale condition was studied. A potential function was introduced and the problem of collision between molecules of argon and molecules in solid wall were dealed with. It is concluded that: when the scale of fluid argon is only one or two OM larger than the effective distance between the solid wall and the molecules of argon, the scale of fluid argon and the molecules of solid wall have remarkable effect on the thermodynamic saturated properties of argon.