北京印刷学院毕业设计（论文）摘要运用分子动力学模拟方法研究了在.doc

摘 要 运用分子动力学模拟方法研究了在质量力驱动下不同浸润性壁面纳米通道中气泡的分布及其运动状 况, 提出了一种统计纳米通道中气泡运动速度的方法. 结果显示, 在亲水性壁面的纳米通道中, 气泡位于通道中 间, 气泡的运动速度接近但小于通道中心流速, 在势能强度较大时, 壁面吸附的分子较多, 气泡也较大, 反之则气 泡较小;对超疏水性壁面, 气泡则位于固壁附近, 两个壁面形成对称的一对气泡, 气泡的运动速度接近但大于边 缘速度. 流体总的流动速度随着流体粒子与壁面粒子作用的减弱而增大,滑移速度则逐渐从负转变为正. 关键词： 分子动力学; 表面浸润性; 纳米气泡; 纳米流动; 纳米通道 中图分类号： O647 Effects of SurfaceWettability on Bubbles in Nanochannels XIE Hui LIU Chao (College of Power Engineering, Chongqing University, Chongqing 400030, P. R. China) Abstract： Molecular dynamics simulations were carried out to study the distribution and movement of bubbles in nanochannels with different wettabilities when the fluids were driven by mass force. A method for calculating the velocity of a bubble in a nanochannel was presented. Results reveal that bubbles are present in the middle of nanochannels with hydrophilic surfaces and their velocities are close to but lower than the flow velocity in the middle of the nanochannel. At higher potential energies, the bubbles are larger because the surface absorbs more particles. Otherwise, the bubbles would be smaller. Two bubbles are symmetrical on both surfaces of the nanochannel when their surfaces are superhydrophobic and their velocities are close to but larger than the flow velocity at the edge of the nanochannel. The fluid flow speeds up as the interaction decreases between fluid molecules and wall particles while the slip velocity gradually changes fromnegative to positive. Key Words： Molecular dynamics; Surface wettability; Nanobubble; Nanoflow; Nanochannel 目 录 1 引言…………………………………………………………………………………2 2 结果与讨论…………………………………………………………………………3 2.1起泡及密度分布…………………………………………………………………3 2.2速度分布…………………………………………………………………………4 2.3起泡的速度………………………………………………………………………4 结论……………………………………………………………………………………5 Ⅰ 1 引言（或绪论） 本文模拟系统的快照如图1 所示, 包含气泡的流体在两固壁形成的纳米通道内由质量力G 驱动,图中蓝色原子代表壁面分子铂, 红色代表流体分子氩, 两壁面都平行于xy 面, x、y 方向为周期性边界条件, z 方向为固壁边界条件. 流体粒子2048 个, 初始位置按fcc 晶格排布. 固壁粒子1