Molecular Dynamics Simulation Of The Viscosity Of Liquid Under Different Pressure And Temperature

Molecular Dynamics Simulation can analyze the nature and characteristics of things by considering the particle movement of molecules. Therefore, it is helpful of further understanding and explanation of many micro and macro phenomena. In particular, when people study the nature of material under extreme conditions, Molecular Dynamics Simulation has become an essential tool. Because water plays a very important role in industrial production, properties of water have been paid much attention. The significance of simulation algorithm study for the important physical parameter, the viscosity of water, is obvious.In this paper, the viscosities of fluid under different temperature and pressure conditions are calculated by molecular dynamics simulation.Based on the basic principles of molecular dynamics, the isothermal and isobaric conditions are introduced, and the formula of fluid's viscosity in the simulation is derived. The viscosities of Argon are simulated by MDS when the temperature is 83K and the pressure is 20MPa. The influence of boundary condition is studied, and this result will benefit the future study of how to decide the statistical area.The viscosities of water in different conditions of temperature and pressure are also calculated by MDS method. For the special structure of water molecules, Long-range Force is considered in the simulations, and the Long-range Force formula of Ewald Summation Method is derived. It makes the simulations more realistic. In order to reduce the computation of works, the Four-element Method is adopted. In this way, the tedious computational work of trigonometric functions is avoided, and the speed of simulation is improved. Finally, the simulation results of the viscosity of water under different temperature and pressure are compared with the experimental data.