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Applied Mathematics and Mechanics(English Edition) 2018年第3期39卷 409-422页

作者： Chuanchuan XIE Bo CHEN Bing YAN Jiankang WU School of Civil Engineering and Mechanics Huazhong University of Science and Technology Department of Mechanical and Electrical Engineering Wenhua College

A field-modulated electroosmotic flow （FMEOF） in a microchannel can be obtained by applying modulating electric fields in a direction perpendicular to the channel wall. Micro-vortexes are generated around the electrodes along with an EOF due to the surface charge on the modulated wall. When polarizable particles are suspended near the electrodes, they experience dielectrophoretic forces due to a non-uniform electric field. In this paper, micro-vortexes and dielectrophoretic forces are combined to achieve separation and trap different sized particles in a continuous flow. Numerical results indicate that by adjusting the driving electric field parallel to the channel wall and the modulating electric field, the ratio of dielectrophoretic and hydrodynamic forces can be altered. One type of particles can be trapped by micro-vortexes （negative dielectrophoresis （DEP））, and the other particles are transported to the downstream so that the particles are separated. The influence of the electrode length and the channel height on the trapping rate is investigated.

关键词： electroosmotic dielectrophoretic micro-vortex particle separation

Rotating electroosmotic flows in soft parallel plate microchannels

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Applied Mathematics and Mechanics(English Edition) 2019年第7期40卷 1017-1028页

作者： Yongbo LIU Yongjun JIAN School of Mathematical Science Inner Mongolia University

We present a theoretical investigation of rotating electroosmotic flows(EOFs) in soft parallel plate microchannels. The soft microchannel, also called as the polyelectrolyte-grafted microchannel, is denoted as a rigid microchannel coated with a polyelectrolyte layer(PEL) on its surface. We compare the velocity in a soft microchannel with that in a rigid one for different rotating frequencies and find that the PEL has a trend to lower the velocities in both directions for a larger equivalent electrical double layer(EDL) thickness λFCL(λFCL = 0.3) and a smaller rotating frequency ω(ω < 5).However, for a larger rotating frequency ω(ω = 5), the main stream velocity u far away from the channel walls in a soft microchannel exceeds that in a rigid one. Inspired by the above results, we can control the EOF velocity in micro rotating systems by imparting PELs on the microchannel walls, which may be an interesting application in biomedical separation and chemical reaction.

关键词： rotating electroosmotic flow (EOF) soft microchannel polyelectrolyte layer (PEL) thickness

Magnetohydrodynamic electroosmotic Flow with Patterned Charged Surface and Modulated Wettability in a Parallel Plate Microchannel

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Communications in Theoretical Physics 2019年第10期71卷 1163-1171页

作者： Na Hao Yong-Jun Jian School of Mathematical Science Inner Mongolia University

This paper investigates the magnetohydrodynamic(MHD) electroosmotic flow(EOF) of Newtonian fluid through a zeta potential modulated parallel plate microchannel with patterned hydrodynamic slippage. The driven mechanism of the flow originates from the Lorentz force generated by the interaction of externally imposed lateral electric field Ey and vertical magnetic field Bz and electric field force produced by an externally applied electric field Ex. It is assumed that the wall zeta potential and the slip length are periodic functions of axial coordinate x, an analytical solution of the stream function is achieved by utilizing the method of separation of variables and perturbation expansion. The pictures of streamlines are plotted and the vortex configurations produced in flow field due to patterned wall potential and hydrodynamic slippage are discussed. Based on the stream function, the velocity field and volume flow rate are obtained, which are greatly depend on some dimensionless parameters, such as slip length ls, electrokinetic widthλ, the amplitude δ of the patterned slip length, the amplitude m of the modulated zeta potential and Hartmann number Ha. The variations of velocity and volume flow rate with these dimensionless parameters are discussed in details. These theoretical results may provide some guidance effectively operating micropump in practical nanofluidic applications.

关键词： magnetohydrodynamic(MHD) flow electroosmotic flow(EOF) modulated hydrodynamic slippage patterned charged surface

Numerical simulation of electroosmotic flow in hydrophobic microchannels

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Science China(Technological Sciences) 2009年第8期52卷 2460-2465页

作者： YANG DaYong LIU Ying School of Mechanical&Electrical Engineering Nanchang UniversityNanchang 330031China

electroosmotic flow(EOF) is a promising way for driving and mixing fluids in *** the parallel-plate microchannel with the hydrophobic surface, this paper solved the governing equations using the finite element method(FEM), and the effects of microchannel height, electric strength and ionic concentration on EOF were thus *** simulation indicates that the transient characteristics of EOF are similar in hydrophobic and hydrophilic microchannels, the steady time of EOF is proportional to the square of microchannel height, and the scale is *** velocity is proportional to the electric strength and independent of the channel height, and decreases slowly with the ionic concentration, which is lower than that in hydrophilic microchannel due to the presence of slip length in hydrophobic *** results can provide valuable insights into the optimal design of microchannel surfaces to achieve accurate EOF control in hydrophobic microchannel.

关键词： microchannel electroosmotic flow(EOF) hydrophobic surface slip length FEM

electroosmotic Water Vapor Transport across Novel, Smart, Functionalized Conducting Polymer Microporous Membranes in Active Mode at Very High Rates, with Concomitant Chemical Warfare (CW) Agent Blocking

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Advances in Materials Physics and Chemistry 2013年第4期3卷 217-237页

作者： Prasanna Chandrasekhar Petar Pirgov Brian J. Zay David Lawrence Sean Morefield Tilghman L. Rittenhouse Salvatore G. Clementi Quoc Truong Russell R. Greene Ashwin-Ushas Corporation Marlboro NJ USA Chemical and Biological Technologies Directorate US Defense Threat Reduction Agency (DTRA) Fort Belvoir VA USA Hazardous Materials Research Center (HMRC) Battelle Columbus Laboratories Battelle Memorial Institute Columbus OH USA US Army Engineer Research and Development Center Construction Engineering Research Laboratory (ERDC-CERL) Champaign IL USA Warrior Science Technology and Applied Research Directorate US Army Natick Soldier Research Development and Engineering (RD&E) Center Natick MA USA

electroosmotic water vapor transport (WVT) across very thin, flexible, functionalized conducting polymer (CP) microporous (μP) membranes at a very high rate is reported. Both passive and active (6 VDC applied) WVT are reported, the latter for the first time ever. WVT occurs with concomitant, effective blocking of chemical warfare (CW) agents, again demonstrated for the first time ever. Initial active liquid||membrane||liquid interface studies demonstrated WVT rates of >1.7 × 10-5g .mm-2s-1, >3 × the highest prior reported values of 5 × ***-2s-1. Subsequent vapor||membrane|| vapor interface studies using industry-standard methods (including ASTM E96B Upright Cup (“WVT”), ASTM F2298 (“Dynamic Moisture Permeation Cell”) and ASTM F1868 (“Sweating Guard Hotplate”) were done at independent, external labs for independent corroboration. These yielded, e.g., WVT values of2564.4 g.m2.d-1 (passive) and3706.7 g.m2d-1 (active), to be compared with the highest (passive) value ever reported previously,984.8 g.m2.d-1 for a μP-Nylon membrane. More than 15 different membrane configurations, porosities and types were studied, including membranes with CP + organophosphate hydrolase (OPH), an enzyme reactive to CW agents. Efficient blocking of the actual CW agents GB, HD, VX is also reported, using the TOP-8-2-501standard. Membranes also passed all Industry-standard durability tests, e.g. ASTM D2261 (Tearing), ASTM D5034 (Breaking), ASTM D3886 (Abrasion), ASTM F392 (Gelbo Flex). Incorporation into smart soldiers’ garments was demonstrated;power consumption was -2. Mechanisms of enhanced WVT and CW agent blocking in the membranes are discussed.

关键词： electroosmotic Transport Smart Microporous Membrane Conducting Polymer Functionalized

Numerical Investigation of Traveling Wave electroosmotic Flows in A Microchannel

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Journal of Biomaterials and Nanobiotechnology 2012年第2期3卷 280-285页

作者： Bo Chen Jiankang Wu Han Chen Mechanics Department Huazhong University of Science and Technology Wuhan China

In this paper, a coordinate transformation method (CTM) is employed to numerically solve the Poisson–Nernst–Planck (PNP) equation and Navier–Stokes (NS) equations for studying the traveling-wave electroosmotic flow (TWEF) in a two-dimensional microchannel. Numerical solutions indicate that the numerical solutions of TWEF with and without the coordinate transformation are in good agreement, while CTM effectively improves stability and convergence rate of the numerical solution, and saves computational cost. It is found that the averaged flow velocity of TWEF in a micro-channel strongly depends on frequency of the electric field. Flow rate achieves a maximum around the charge frequency of the electric double layer. The approximate solutions of TWEF with slip boundary conditions are also presented for comparison. It is shown that the NS solution with slip boundary conditions agree well with those of complete PNP-NS equations in the cases of small ratios of Electric double layer(EDL) thickness to channel depth(λD/H). The NS solution with slip boundary conditions over-estimates the electroosmotic flow velocity as this ratio(λD/H) is large.

关键词： Traveling-Wave electroosmotic Flow (TWEF) Coordinate Transformation Method(CTM) Electric Double Layer (EDL) Poisson-Nernst-Planck(PNP) Equations

Principle of a Multistage electroosmotic Pump and Its Application in Microfluidic Chip

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高等学校化学学报 2004年第Z1期25卷 30-页

作者： CHEN Ling-Xina GUAN Ya-Feng Department of Chemistry Tsinghua University Beijing 100084 China Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116012 China

　　In the past decade, a variety of microfabricated pumps and fluid-handling systems based on ultrasonic, electricity, light, magnet and heat actuated technologies were reported[1], which could be classified into two groups: membrane-displacement pumps and field-induced flow pumps. An advantage of field-induced flow pumps over the former is that they do not require moving parts, such as check valves which complicate the fabrication, sealing, and operation of the systems.……

关键词： electroosmotic pump Multi-stage Micro total analysis system

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两种填充型双电渗泵的制作与流量控制

色谱 2007年第3期25卷 435-436页

作者：尤慧艳郭明张丽华张维冰张玉奎大连大学环境与化学工程学院辽宁大连116622 中国科学院大连化学物理研究所国家色谱研究分析中心辽宁大连116023

自制了同柱双电渗泵和异柱双电渗泵,考察了这两种填充型双电渗泵的泵流速及流量与驱动电压的关系,并将其与填充型单电渗泵进行了比较,说明了其优势。

关键词：填充柱(packed column) 双电渗泵(double electroosmotic pump) 微流(microflow)

NEW APPROACH TO MINIMIZE DISPERSION INDUCED BY TURN IN CAPILLARY ELECTROPHORESIS CHANNEL FLOWS

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Applied Mathematics and Mechanics(English Edition) 2005年第6期26卷 685-690页

作者：李志华林建忠聂德明 Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Zhejiang University of Science and Technology Hangzhou 310012P.R.China

The mechanism of dispersion induced by turn in the capillary electrophoresis channel flows was analyzed firstly. Then the mathematical model of electroosmotic flow is built, and the dispersion of the flow, with different distribution of charge at inner and outer wall in the turns, was simulated numerically using the finite differential method. A new approach of altering the distribution of charge at inner and outer wall in the turns was presented, based on the computational results, to minimize the dispersion induced by turn. Meanwhile, an optimization algorithm to analyze the numerical results and determine the optimal distribution of charge in the turns was also developed. It is found that the dispersion induced by turn in the capillary electrophoresis channel flows could be significantly suppressed by this approach.

关键词： micro-flow electrophoresis electroosmotic dispersion turn