摘要
目的研究非对称性通道中亲疏水表面结构影响下纳米气泡特征与边界滑移之间的关系,以实现良好的流体减阻效果。方法采用二元体系分子动力学方法,研究纳米气泡在通道流动中产生的滑移减阻效应。首先建立上下壁面非对称微通道模型,通过考虑微通道流动传热过程,探究纳米气泡影响下的微通道界面速度滑移现象。结果保持亲水下壁面高度以及上下壁面温差不变的情况下,增加上壁面纳米结构高度,对通道中纳米气泡体积产生促进作用。另外,当上壁面为疏水壁面时,气泡呈现为壁面形式,并且随着体积增大,相对应通道中上壁面滑移长度增大;当上壁面为亲水壁面时,纳米气泡呈现为体相形式,并且随着体积增大,对应上壁面滑移长度减小。结论非对称性通道内,在上壁面结构高度影响下,壁面形式的气泡体积增大对通道内减阻具有促进作用,而体相形式的气泡体积增大对通道内减阻具有抑制作用。
The purpose of this paper is to achieve a good fluid drag reduction effect by studying the relationship between the characteristics of nanobubbles and boundary slip under the influence of hydrophilic and hydrophobic surface structures in asymmetric channels.In this paper,the binary system molecular dynamics method is used to study the slip drag reduction effect of nanobubbles flowing in the channel.Firstly,the asymmetric microchannel model on the upper and lower walls is established,and the microchannel interface velocity slip phenomenon under the influence of nanobubbles is explored by considering the flow and heat transfer process of the microchannel.The simulation results show that when keeping the height of the hydrophilic lower wall and the temperature difference between the upper and lower walls unchanged,the increase in the height of the nanostructures on the upper wall promotes the volume increase of nanobubbles in the channel;in addition,when the upper wall is a hydrophobic wall,the nanobubbles appear in the form of a wall surface.As the volume increases,the slip length of the upper wall in the corresponding channel increases;when the upper wall is a hydrophilic wall,the nanobubbles are in bulk form,and as the volume increases,the corresponding upper wall’s slip length is reduced.In an asymmetrical channel,under the influence of the height of the upper wall structure,the increase of the nanobubble volume in the form of a wall surface promotes the drag reduction in the channel,while the increase of the nanobubble volume in the bulk form inhibits the drag reduction in the channel.Therefore,the research results in this paper provide a theoretical basis for exploring the application of nanobubble engineering in drag reduction.
作者
戴双武
卢艳
高友明
李扬帆
DAI Shuang-wu;LU Yan;GAO You-ming;LI Yang-fan(Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,China;Key Laboratory of Mechanical Transmission and Manufacturing Engineering,Wuhan University of Science and Technology,Wuhan 430081,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2022年第2期202-210,共9页
Surface Technology
基金
国家自然科学基金(51875417,51975425)。
关键词
微通道
温度阶跃
速度滑移
纳米气泡
滑移减阻
润湿性
microchannel
temperature step
velocity slip
nanobubbles
slip drag reduction
wettability
