纳米受限效应下流体自扩散机理及规律研究  

Investigation on Self-Diffusion of Fluid under Nanoconfinement Effect

作　　者：曾克成 姜培学[1] 胥蕊娜[1] ZENG Kecheng;JIANG Peixue;XU Ruina(Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]热科学与动力工程教育部重点实验室,清华大学能源与动力工程系,北京100084

出　　处：《工程热物理学报》2024年第3期778-784,共7页Journal of Engineering Thermophysics

基　　金：国家自然科学基金杰出青年基金项目(No.52225603)。

摘　　要：当固体壁面间距仅有几个纳米时,纳米受限效应使得流体自扩散系数降低12个数量级,孔径、温度和压力的影响显著且复杂。分析受限流体扩散机理和规律,建立简洁的关联式具有重要意义。本研究从分子模拟出发,经过仔细计算和分析,获得了大量纳米孔隙中流体自扩散系数数据。分析了壁面吸附作用对流体扩散的影响机理和规律,提出了可简单描述流体扩散行为的无量纲扩散系数,从而与努森数建立相应关联式,具有较强的适用性。When the distance between solid walls is only a few nanometers,the self-diffusion co-efficient of fluid is reduced by 1∼2 orders of magnitude due to the nanoconfinement effect,and the effects of pore size,temperature and pressure are significant and complex.It is of great significance to analyze the diffusion mechanism and law of nanoconfined fluid and establish a concise correla-tion formula.In this study,a wide range of fluid self-diffusion coefficient data in nanopores were obtained through careful calculation and analysis based on molecular dynamics simulation.The mechanism and law of the adsorption effect on fluid diffusion were analyzed,and a novel dimen-sionless diffusion coefficient,which can simply describe the fluid diffusion behavior,was proposed,and the corresponding correlation formula was established with Knudsen number,which has strong applicability.

关 键 词：纳米受限 流体扩散 分子动力学 

分 类 号：TK123[动力工程及工程热物理—工程热物理]