Scale effect on flow and thermal boundaries in micro-/nano-channel flow using molecular dynamics-continuum hybrid simulation method
Scale effect on flow and thermal boundaries in micro-/nano-channel flow using molecular dynamics-continuum hybrid simulation method
复制标题
使用分子动力学-连续介质混合模拟方法研究微/纳米通道流动中流动和热边界的尺度效应
DOI：
10.1002/nme.2683
复制
发表时间：
2010-01-08
影响因子：
2.9
通讯作者：
Tao, Wen-Quan
中科院分区：
文献类型：
--
作者：
Sun, Jie;He, Ya-Ling;Tao, Wen-Quan
本文从两个方面发展了分子动力学（MD）-连续介质混合模拟方法：（1）将能量方程引入耦合方法，得到混合温度分布;（2）通过局部线性化改进耦合方法，得到更光滑的参数分布。所开发的方法主要通过解析解和全MD结果进行验证。然后，研究了微纳通道流动中流动和热边界的尺度效应。在通道高度（H）从60 σ到2014 σ的范围内和固液耦合（β）从0.1到50的范围内获得混合速度和温度分布。尺度效应对边界有很强的影响。当H较小时，β较大时，剖面中存在明显的滑移特征，即速度滑移和温度跃变。然而，结果也表明，可以很好地预测的轮廓收敛到宏观尺度的无滑移/无跳跃的分析时，H是足够大的，其中的影响可以忽略β和滑移特性消失。根据模拟结果拟合了相对滑移长度、相对温度跃变和压力梯度与H的关系。版权所有（C）2009约翰威利父子有限公司
The molecular dynamics (MD)-continuum hybrid simulation method has been developed in two aspects in the present work: (1) The energy equation has been combined into the coupling method in order to obtain the hybrid temperature profile and (2) the coupling method has been improved by the local linearization to obtain a smoother parametric profile. The developed method is primarily validated by analytical Solutions and full MD results. Then, it is employed to Study the scale effect oil the flow and thermal boundaries in micro-/nano-channel flow. The hybrid velocity and temperature profiles are obtained with the channel height (H) ranging from 60 sigma to 2014 sigma and the solid-liquid coupling (beta) ranging from 0.1 to 50. Scale effect has shown strong influence on the boundaries. Obvious slip characteristics can be found in the profiles, i.e. velocity slip and temperature jump, when H is small and beta is large. However, the results also show that the profiles can be well predicted to converge to the macroscale non-slip/non-jump analytical when H is large enough, where the effect of beta can be omitted and the slip characteristics disappear. Correlations of relative slip length, relative temperature jump and pressure gradient with H are fitted from the simulation results. Copyright (C) 2009 John Wiley & Sons, Ltd.