磁场下微通道中磁-非磁液界面不稳定性分析

doi:10.16085/j.issn.1000-6613.2023-1004

摘要/Abstract

摘要：

微通道中稳定、清晰的界面是进行颗粒进一步筛选的重要基础，将磁液作为核心流，非磁液作为鞘流有利于颗粒在外加磁场作用下进行微流控聚焦。本文基于对三相层流微流控芯片中磁液-水界面实验分析和力学模型求解，引入量纲为1数Pe、Bo_m、Ca、W、Re，以及表征界面颗粒运动状态的时间t_T、t_d、t_i，得到d/h∝(X/Pe)^0.633~0.852界面上力的大小依次为：磁力>界面张力>惯性力>黏性力。Q_w/Q_f=2，Q_f=15μL/min时，核心流的黏性耗散影响较小，界面位于通道中心处较为稳定。界面磁颗粒扩散时间t_d∝(X/Pe)^0.523~0.872在入口阶段振荡剧烈，加速流体混合，同时磁场梯度和流体扩散速度的增大会导致界面时间t_i∝(X/Pe)^0.778~1.172剧烈变化，当X=225～250时，t_T>t_i>t_d，颗粒聚焦效率最高。

关键词: 微通道, 对流扩散, 磁力, 界面张力, 黏性力

Abstract:

The stable and clear interface in the microchannel is an important basis for further particle screening. Using the ferrofluid as the core flow and the non-magnetic fluid on both sides as the sheath flow is conducive to microfluidic focusing of particles under magnetic field. This paper is based on the experimental analysis of the ferrofluid-water interface in three-phase laminar microfluidic chip and the solution of the mechanical model. The dimensionless numbers Pe, Bo_m, Ca, We, Re, and the time t_T, t_d, t_ito represent the movement state of the particles at the interface were introduced, and it obtained d/h∝(X/Pe)^0.633~0.852. The effect of each force on the interface was in the order of magnetic force greater than interfacial tension, inertial force, and viscous force. When Q_f/Q_w=2, Q_f=15μL/min, the convective effect was obviously greater than the diffusion effect. In this case, the viscous dissipation effect of particles was small, and the interface was stable at the center of the channel. The diffusion time t_d∝(X/Pe)^0.523~0.872 oscillated violently at the entrance stage, accelerating fluid mixing. Meanwhile, the increase of magnetic field gradient and fluid diffusion velocity will lead to a drastic change in interfacial time t_i∝(X/Pe)^0.778~1.172. When X=225—250 in the middle of the magnetic field, t_T>t_i>t_d, and the screening efficiency of magnetic swimming was the highest.

Key words: microchannels, convective diffusion, magnetic force, interfacial tension, viscous force

中图分类号:

O359.1

闻桂叶, 焦凤, 何永清. 磁场下微通道中磁-非磁液界面不稳定性分析[J]. 化工进展, 2024, 43(7): 3787-3797.

WEN Guiye, JIAO Feng, HE Yongqing. Analysis of ferrofluids-nonferrofluids interface instability in microchannels under magnetic field[J]. Chemical Industry and Engineering Progress, 2024, 43(7): 3787-3797.

图/表 9

图1 Y型微通道和T型微通道示意图（a）和磁液-非磁液界面受力分析示意图（b）

图2 磁颗粒在通道中的运动时间tT、扩散时间td、界面时间ti示意图

图3 微通道和永磁体的空间尺寸（a）、相对位置（b）和整体系统装置图（c）

表1 磁液/去离子水物性参数

参数	描述	符号	数值	单位
磁液	磁液饱和磁矩	M_sat	16560	A/m
	Fe₃O₄纳米粒子平均直径	d	10	nm
	动力黏度	η_f	1.6×10^-3	N·s/m²
	磁液磁化系数	χ_f	0.56
	磁粒子磁化系数	χ_p	20
	密度	ρ_f	1190	kg/m³
去离子水	密度	ρ_w	1000	kg/m³
	动力黏度	η_w	0.8937×10^-3	N·s/m²

图4 实验数据后处理示意图

图5 磁液入口流量对界面的影响（Qw/Qf=2）Qf=3μL/min（a）、Qf=5μL/min（b）、Qf=10μL/min（c）、Qf=15μL/min（d）、Qf=20μL/min（e）、核心流宽度分数分布（f）、界面附近磁液的计算流速与实验测量结果对比图（g）

图6 Qf=3～20μL/min时界面Pe/Pemax（a）、x方向和y方向的磁力示意图（b）和通道长度方向10～30mm界面Bom分布（c）

图7 磁液入口流量Qf=3μL/min（a）、5μL/min（b）、10μL/min（c）、15μL/min（d）、20μL/min（e）时磁颗粒在通道中的运动时间tT、扩散时间td和界面时间ti以及tT/ti沿通道长度的分布（f）

图8 磁液入口流量Qf为3～20μL/min时界面的Ca（a）、Re（b）、We（c）和界面黏性力分布（d）

参考文献 29

1	陈娅君, 龙威, 何永清, 等. 液-液多相流微萃取的数值模拟和实验分析[J]. 化工进展, 2019, 38(5): 2085-2092.
	CHEN Yajun, LONG Wei, HE Yongqing, et al. Numerical simulation and experimental analysis of liquid-liquid multiphase microextraction[J]. Chemical Industry and Engineering Progress, 2019, 38(5): 2085-2092.
2	TARN M D, LOPEZ-MARTINEZ M J, PAMME N. On-chip processing of particles and cells via multilaminar flow streams[J]. Analytical and Bioanalytical Chemistry, 2014, 406(1): 139-161.
3	LEE Sang Wook, YAMAMOTO T, NOJI H, et al. Chemical delivery microsystem for single-molecule analysis using multilaminar continuous flow[J]. Enzyme and Microbial Technology, 2006, 39(3): 519-525.
4	田启凯, 郑海萍, 张少斌, 等. 混合增强的微流控通道进展[J]. 化工进展, 2023, 42(4): 1677-1687.
	TIAN Qikai, ZHENG Haiping, ZHANG Shaobin, et al. Advances in mixing enhanced microfluidic channels[J]. Chemical Industry and Engineering Progress, 2023, 42(4): 1677-1687.
5	ALORABI A Q, TARN M D, GÓMEZ-PASTORA J, et al. On-chip polyelectrolyte coating onto magnetic droplets-Towards continuous flow assembly of drug delivery capsules[J]. Lab on a Chip, 2017, 17(22): 3785-3795.
6	TARN M D, PAMME N. On-chip magnetic particle-based immunoassays using multilaminar flow for clinical diagnostics[M]// Microchip Diagnostics. New York: Humana Press, 2017: 69-83.
7	CAPRETTO L, CHENG Wei, HILL M, et al. Micromixing within microfluidic devices[J]. Topics in Current Chemistry, 2011(304): 27-68.
8	GÓMEZ-PASTORA J, GONZÁLEZ-FERNÁNDEZ C, FALLANZA M, et al. Flow patterns and mass transfer performance of miscible liquid-liquid flows in various microchannels: Numerical and experimental studies[J]. Chemical Engineering Journal, 2018, 344: 487-497.
9	ZHAO Wujun, CHENG Rui, So Hyun LIM, et al. Biocompatible and label-free separation of cancer cells from cell culture lines from white blood cells in ferrofluids[J]. Lab on a Chip, 2017, 17(13): 2243-2255.
10	HUANG Wei, WANG Xiaolei. Ferrofluids lubrication: A status report[J]. Lubrication Science, 2016, 28(1): 3-26.
11	TORRES-DÍAZ I, RINALDI C. Recent progress in ferrofluids research: Novel applications of magnetically controllable and tunable fluids[J]. Soft Matter, 2014, 10(43): 8584-8602.
12	JIAO Feng, LI Qian, HE Yongqing. Electromotive force induced by the moving non-magnetic phase in ferrofluids[J]. Sensors and Actuators A: Physical, 2021, 317: 112472.
13	JIAO Feng, LI Qian, JIAO Yanying, et al. Heat transfer of ferrofluids with magnetoviscous effects[J]. Journal of Molecular Liquids, 2021, 328: 115404.
14	汪伟, 苏瑶瑶, 刘壮, 等. 微流控法可控构建微尺度功能材料[J]. 化工进展, 2019, 38(1): 421-433.
	WANG Wei, SU Yaoyao, LIU Zhuang, et al. Controllable microfluidic fabrication of microscale functional materials[J]. Chemical Industry and Engineering Progress, 2019, 38(1): 421-433.
15	陈宏霞, 肖红洋, 孙源, 等. 不同T型微通道内弹状流相分离规律的实验研究[J]. 高校化学工程学报, 2020, 34(4): 912-918.
	CHEN Hongxia, XIAO Hongyang, SUN Yuan, et al. Experimental study on phase separation of slug flow in different T-type microchannels[J]. Journal of Chemical Engineering of Chinese Universities, 2020, 34(4): 912-918.
16	刘浪宇, 朱春英, 马友光, 等. 微通道内表面活性剂与界面传递现象研究进展[J]. 化工学报, 2021, 72(2): 783-798.
	LIU Langyu, ZHU Chunying, MA Youguang, et al. Progress on surfactant and interfacial transport phenomena in microchannels[J]. CIESC Journal, 2021, 72(2): 783-798.
17	钱锦远, 李晓娟, 吴赞, 等. 微通道内液-液两相流流型及传质的研究进展[J]. 化工进展, 2019, 38(4): 1624-1633.
	QIAN Jinyuan, LI Xiaojuan, WU Zan, et al. Research progress on flow regimes and mass transfer of liquid-liquid two-phase flow in microchannels[J]. Chemical Industry and Engineering Progress, 2019, 38(4): 1624-1633.
18	SOTOWA K. Fluid behavior and mass transport characteristics of gas-liquid and liquid-liquid flows in microchannels[J]. Journal of Chemical Engineering of Japan, 2014, 47(3): 213-224.
19	ZHOU Ran, WANG Cheng. Multiphase ferrofluid flows for micro-particle focusing and separation[J]. Biomicrofluidics, 2016, 10(3): 034101.
20	ZHAO Bin, VIERNES N O L, MOORE J S, et al. Control and applications of immiscible liquids in microchannels[J]. Journal of the American Chemical Society, 2002, 124(19): 5284-5285.
21	HIBARA A, NONAKA M, HISAMOTO H, et al. Stabilization of liquid interface and control of two-phase confluence and separation in glass microchips by utilizing octadecylsilane modification of microchannels[J]. Analytical Chemistry, 2002, 74(7): 1724-1728.
22	ATENCIA J, BEEBE D J. Controlled microfluidic interfaces[J]. Nature, 2005, 437(7059): 648-655.
23	ÍM COUTINHO, MIRANDA J A. Development of magnetoelastic fingering patterns in a rectangular Hele-Shaw cell[J]. Physical Review Fluids, 2020, 5(9): 094002.
24	YECKO P. Effect of normal and parallel magnetic fields on the stability of interfacial flows of magnetic fluids in channels[J]. Physics of Fluids, 2010, 22(2): 022103.
25	MALEKI M A, ZHANG Jun, KASHANINEJAD N, et al. Magnetofluidic spreading in circular chambers under a uniform magnetic field[J]. Microfluidics and Nanofluidics, 2020, 24(10): 80.
26	ZHAO Wujun, CHENG Rui, MILLER J R, et al. Label-free microfluidic manipulation of particles and cells in magnetic liquids[J]. Advanced Functional Materials, 2016, 26(22): 3916-3932.
27	THANJAVUR KUMAR D, ZHOU Yilong, BROWN V, et al. Electric field-induced instabilities in ferrofluid microflows[J]. Microfluidics and Nanofluidics, 2015, 19(1): 43-52.
28	WANG Zhaomeng, VARMA V B, XIA Huanming, et al. Spreading of a ferrofluid core in three-stream micromixer channels[J]. Physics of Fluids, 2015, 27(5): 052004.
29	CUBAUD T, MASON T G. Formation of miscible fluid microstructures by hydrodynamic focusing in plane geometries[J]. Physical Review E, 2008, 78(5): 056308.

[1]	王彦红, 蒋雷, 薛帅, 李洪伟, 贾玉婷. 预冷通道中超临界甲烷换热特性分析[J]. 化工进展, 2024, 43(4): 1690-1699.
[2]	李文鹏, 刘晴, 杨志荣, 高展鹏, 王景涛, 周鸣亮, 张金利. 液相剥离法高效制备石墨烯的研究进展[J]. 化工进展, 2024, 43(1): 215-231.
[3]	赵晨, 苗天泽, 张朝阳, 洪芳军, 汪大海. 负压状态窄缝通道乙二醇水溶液传热特性[J]. 化工进展, 2023, 42(S1): 148-157.
[4]	王太, 苏硕, 李晟瑞, 马小龙, 刘春涛. 交流电场中贴壁气泡的动力学行为[J]. 化工进展, 2023, 42(S1): 133-141.
[5]	陈蔚阳, 宋欣, 殷亚然, 张先明, 朱春英, 付涛涛, 马友光. 矩形微通道内液相黏度对气泡界面的作用机制[J]. 化工进展, 2023, 42(7): 3468-3477.
[6]	俞俊楠, 俞建峰, 程洋, 齐一搏, 化春键, 蒋毅. 基于深度学习的变宽度浓度梯度芯片性能预测[J]. 化工进展, 2023, 42(7): 3383-3393.
[7]	陶梦琦, 刘美红, 康宇驰. 基于micro-PIV的微通道内流体绕流单微圆柱和并联双微圆柱流场特性[J]. 化工进展, 2023, 42(6): 2836-2844.
[8]	田启凯, 郑海萍, 张少斌, 张静, 余子夷. 混合增强的微流控通道进展[J]. 化工进展, 2023, 42(4): 1677-1687.
[9]	罗小平, 樊鹏, 周建阳, 王梦圆. 不同波纹壁面微细通道沸腾曲线及沸腾起始点研究[J]. 化工进展, 2023, 42(3): 1228-1239.
[10]	黄起中, 刘冰, 马红鹏, 吕文杰. 基于新型微通道分离技术的甲醇制烯烃废水处理[J]. 化工进展, 2023, 42(2): 669-676.
[11]	马跃, 王钦艳, 金央. 麻花式插件微通道中游离脂肪酸预酯化[J]. 化工进展, 2023, 42(12): 6191-6196.
[12]	刘兆轩, 张程宾, 韩群, 姜海涛, 李文明. 锯齿型微通道流动与传热特性数值模拟[J]. 化工进展, 2023, 42(11): 5622-5636.
[13]	韩昌亮, 黄峄演, 徐建全. 不同结构凹穴微通道内超临界氮气流动与传热特性[J]. 化工进展, 2023, 42(11): 5592-5601.
[14]	宋超, 叶学民, 李春曦. 纳米颗粒与表面活性剂的自组装行为对硅油-水界面性质影响的分子动力学[J]. 化工进展, 2022, 41(S1): 366-375.
[15]	陈秋实, 郑辰, 张敏弟. 微通道反应器氯磷酸单丁酯与正丁醇酯化反应数值模拟[J]. 化工进展, 2022, 41(S1): 29-35.