電流變液電動力壓力驅動流之流態與流動電位分析

Electrokinetic Pressure-Driven Flows and Streaming Potential Effects of Electrorheological Liquids

張嘉倫(Chia-Lun Chang)

指導教授 ： 黃信富

國立臺灣大學/工學院/機械工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201600682

摘要

微流體系統(Microfluidic System)近年來在各領域受到相當多的關注與研究，也由於應用在微觀尺度的流場，使得微流體系統多半須考慮電雙層結構(Electrical Double Layer)的存在以及電動力學現象(Electrokinetic Phenomena)對流場所造成的影響。在先前的研究中，大多使用牛頓流體或是冪次型之非牛頓流體(廣義牛頓流體)作為研究的對象流體。然而，若考慮現今微流系統所應用之領域，其工作流體多半屬於具有微量異質微粒之懸浮溶液，單以廣義牛頓流體作為模型不足以詮釋流體之動力表現，故本研究選擇以正電流變流體作為工作流體模型，並結合電動力現象，探討電流變流體壓力驅動流所誘發之流動電位與電流變效應。吾人利用微極化(Micro-Polar)流體之線動量與角動量統馭方程式，考慮流場中最小連體單元(流體包裹)之極化鬆弛現象，將流動電位所形成之空間誘導電場對電流變液所造成的額外體電力矩納入考量，並求取流場中的角速度、線速度及誘導電場強度的半解析解。最後，本研究對不同參數下之流體包裹旋轉角速度、流體線速度、流場上下游所能建立之誘導電場以及最終流體運動之體積流率進行討論。

關鍵字

壓力驅動流 ； 電流變懸浮液流體 ； 流動電位 ； 電黏滯性 ； 自旋黏滯係數

並列摘要

Recently, microfluidic systems have drawn lots of research interest due to its wide applications in many industrial or scientific fields. Because the scale of the flow channel is reduced to micrometer, we usually need to take the electrical double layer structure and the associated electrokinetic phenomena into consideration when dealing with microfluidic systems. In previous literature, many researchers have employed Newtonian or power-law non-Newtonian fluid as the working fluid in microfluidic systems. Both of these two models cannot accurately describe what is really happening inside the microfluidic systems since most of the working fluids processed in microfluidic systems are solid particle – liquid suspensions. Also, the electrokinetic phenomenon may have interactions with these suspension particles. Hence, in this thesis, we consider and analyze the electrorheological and streaming potential effects induced by electrokinetic pressure driven flows of electrorheological suspension liquids.
Additional to the continuum linear and angular momentum equations of electrorheological micro-polar fluids, we further introduce the electrical streaming potential effect as well as the electrical torque generated via the fluid polarization andstreaming potential electrical field into the modeling of the electrorheological flow field. After obtaining semi-analytical solutions, we discuss the spin velocity, linearvelocity, streaming potential, and the volumn flow rate on the various parametersrelevant to the flow situation considered herein.

並列關鍵字

pressure driven flow ； electrorheological suspension liquids ； streaming potential ； electroviscous effect ； spin viscosity

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