TTCF Method On The Calculation Of Nano Scale Boundayr Layer Flow Velocity

With the rapid development of modern science and nanotechnology, the behavior of nanoscale fluid has been attracting more and more attention. The velocity of flow is an important parameter reflecting the characteristics of the current. As the difficulties of experimental, molecular dynamics simulations has been a powerful tool to explore nanoflow problems. The flow velocity got by traditional molecular dynamics method is the average value of bulk flow velocity and the molecules’thermal motion over time. For low speed flow problems, because of the highly nonlinear coupling of the low bulk flow velocity and the high velocity of molecules’thermal motion, and usually over-estimate the true flow velocity in such cases and lose its authenticity. Calculation of flow velocity in low speed nanoflow problems is the basis for nanoflow problems. So, on this issue more in-depth study is necessary.This paper is based on the theory of phase space, use a new method (transient-time correlation function method) which combining the knowledge of time correlation function and molecular dynamics to solving the flow parameters such as flow velocity and stress. Firstly, two kinds of solution method of flow velocity in nanoflow system were described and compared to provide theoretical foundation and prerequisite for molecular simulation calculation. Then, model building, in the state of constant temperature, simulation of three-dimensional flow in liquid argon in the channel. Solve the fluid velocity and other parameters by the traditional method and the new method in different wall potential constants and different external force field, and statistical the data. the research findings suggest that the velocity datas obtained by the new method and the traditional numerical methods are very coincided. This shows that, using the new method is feasible. At the same time, through further study showed that the calculated results obtained by the new method with better accuracy and stability. Moreover, the new method has more obvious advantage is to solve the problem of traditional methods can not accurately calculate the low speed flow. The main content of study include fluid velocity distribution, stress distribution, viscosity and density distribution, the study obtained many important conclusions.