物理学报2026，Vol.75Issue(7)：444-463,20.DOI:10.7498/aps.75.20251582
高Zeta势下一类矩形微管道中由振荡电渗流引起的物质输运与分离现象研究
Research on the mass transfer and separation phenomena of species by oscillatory electroosmotic flows for a type of micro-nano fluids in a rectangular microchannel under high Zeta potential
摘要
Abstract
Microfluidic technology,with its miniaturization,high-throughput,and low sample consumption characteristics,has become a core technology in the fields of chemical sensing,targeted drug delivery,and biomolecular separation.Electroosmotic flow,as a key driving mechanism in microfluidics,can effectively enhance mass transport and separation efficiency by modulating the flow field structure through periodic oscillation.Building on this,the present study reveals the intrinsic coupling mechanisms among oscillating electric fields,flow field structures,and solute transport.Moreover,through parameter regulation,it enables the active design and optimization of mixing,reaction,and separation processes in microfluidic chips. In this study,the flow characteristics of the periodically oscillating electroosmotic flow and the resulting mass transport and separation mechanisms are investigated for a class of micro-nano fluids in rectangular microchannels under high Zeta potential conditions.The finite difference method and numerical integration are used to calculate the electric double layer potential,velocity field,concentration field,and the spatiotemporal average mass transport rate,respectively.The effects of relevant parameters,such as the wall Zeta potential,Debye length,Womersley number,and Schmidt number are analyzed on both the fluid flow characteristics and the resulting mass transport and separation mechanisms.The results show that:1)the velocity profile is significantly regulated by the Womersley number,when the Womersley number is small,the flow exhibits a quasi-steady plug-like profile with uniform velocity distribution in the channel center;as the Womersley number increases,inertial effects dominate,leading to phase lag,shear layers,and localized flow reversal in the velocity distribution;2)high wall Zeta potential enhances the electroosmotic driving force,but maintaining a fixed tidal displacement results in a decrease in the Peclet number,thereby attenuating the convective effect;3)the analysis for the concentration field reveals that mass transport is governed by the convection-diffusion balance,with concentration gradients highly concentrated near the walls and the center concentration gradients approaching zero;a smaller Debye length results in a more localized electroosmotic forcing near the walls,leading to sharper concentration gradients;a larger Debye length produces smoother concentration gradients;under asymmetric wall Zeta potential,the concentration distribution exhibits spatial asymmetry,with a steeper gradient on the side of higher Zeta potential;4)quantification of spatiotemporal average mass transport rates shows that a larger tidal displacement amplifies convective contributions,further increasing the mass transport rate;an asymmetric Zeta potential configuration enhances mass transport by inducing flow asymmetry;the transport rate increases with the Womersley number,and the species with a larger Schmidt number(smaller diffusion coefficient)exhibit higher transport rates,and a crossover phenomenon is observed;this indicates that at specific frequencies,the transport rate curves of different diffusive species intersect,thus enabling the possibility of species separation.关键词
高Zeta势/振荡电渗流/物质输运与分离/有限差分法/交叉现象Key words
high Zeta potential/oscillatory electroosmotic flow/mass transport and separation/finite difference method/crossover phenomenon引用本文复制引用
张宗贤,陈小刚,崔继峰,乔煜然,臧孝楠,王怀贞..高Zeta势下一类矩形微管道中由振荡电渗流引起的物质输运与分离现象研究[J].物理学报,2026,75(7):444-463,20.基金项目
国家自然科学基金(批准号:12172333)、内蒙古自治区高等学校青年科技英才支持计划(批准号:NJYT22075)、内蒙古自然科学基金(批准号:2025LHMS01005,2025LHMS01010)、内蒙古自治区直属高校基本科研业务费(批准号:JY20220331)资助的课题. Project supported by the National Natural Science Foundation of China(Grant No.12172333),the Support Program for Young Scientific and Technological Talents of Colleges and Universities of Inner Mongolia Autonomous Region,China(Grant No.NJYT22075),the Natural Science Foundation of Inner Mongolia,China(Grant No.2025LHMS01005,2025LHMS01010),the Basic Scientific Research Funds of Universities Directly Under the Inner Mongolia Autonomous Region,China(Grant No.JY20220331). （批准号:12172333）
