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標題: 帶電圓管奈米流道電動效應之研究
Electrokinetic Effects in Charged Nanoscale Capillaries
作者: 三政鴻
San, Zheng-Hong
關鍵字: Electrokinetic effect;電動效應;Streaming potential;Nanoscale capillaries;流動電位;奈米圓管
出版社: 機械工程學系所
引用: 【1】W.B. Russel, D.A Saville, W.R. Schowalter, Colloidal dispersions Cambridge monographs on mechanics and applied mathematics, Cambridge university press, 1981. 【2】R.J. Hunter, Zeta potential in colloid science:principles and applica- tions, Academic press, New York, 1981. 【3】C. Yang, D. Li, Analysis of electrokinetic effects on the liquid flow in rectangular microchannels, Colloids And Surface A143 (1998) 339-353. 【4】H.J. Keh, H.C. Tseng, Transient electrokinetic flow in fine capillaries, Journal of Colloid and Interface Science 242 (2001) 450- 459. 【5】J. Yang, D.Y. Kwok, Effect of liquid slip in electrokinetic parallel plate microchannel flow, Journal of Colloid and Interface Science 260 (2003) 225-233. 【6】J.Yang, A.Bhattacharyya, J.H. Masliyah, D.Y. Kwok, Oscillating laminar electrokinetic flow in infinitely extended rectangular micro channels, Journal of Colloid and Interface Science 261 (2003) 21-31. 【7】X.Y. Chen, K.C. Toh, J.C. Chai, C. Yang, Developing pressure driven liquid flow in microchannels under the electrokinetic effect, International Journal of Engineering Science, 42 (2004) 609-622. 【8】H. Daiguji, P. Yang, A.J. Szeri, A. Majumdar, Electrochemomecha- nical energy conversion in nanofluidic channels, Nano Letters Vol.4 No.12 (2004) 2315-2321. 【9】F. Lu, J. Yang, D.Y. Kwok, Flow field effect on electric double layer during streaming potential measurements, Journal of Physical Chemistry B 108 (2004) 14970-14975. 【10】R. Qiao, N.R. Aluru, Atomistic simulation of KCl transport in charged silicon nanochannels:Interfacial effects, Colloid and Surface A:Physical Chemistry Engineering Aspects 267 (2005) 103-109. 【11】van der Heyden, F.H. J, S. Derek, D. Cees, Streaming currents in a single nanofluidic channel, Physical Review Letters PRL 95 (2005) 116104. 【12】A. Mansouri, C. Scheuerman, S. Bhattacharjee, D.Y. Kwok, L.W. Kostiuk, Transient streaming potential in a finite length microchannel, Journal of Colloid and Interface Science 292 (2005) 567-580. 【13】D.N. Petsev, G.P. Lopez , Electrostatic potential and electroosmotic flow in a cylindrical capillary filled with symmetric electrolyte: Analytic solutions in thin double layer approximation , Journal of Colloid and Interface Science 294 (2006) 492-498. 【14】K.D. Huang,R.J. Yang, Electrokinetic behaviour of overlapped electric double layer in nanofluidic channels, Nanotecnology 18 (2007) 115701-115706. 【15】S.T. Cui, H.D. Cochran, Electroosmotic flow in nanoscale parallel plate channels : Molecular simulation study and comparison with classical Poisson Boltzmann theory, Molecular Simulation Vol.30 (2004) 259-266. 【16】X. Xuan, D. Li, Thermodynamic analysis of electrokinetic energy conversion, Journal of Power Sources 156 (2005) 677-684. 【17】W. Olthuis, B. Schippers, J. Eijkel, A. van der Berg, Energy from streaming current and potential, Sensors and Actuators B 111-112 (2005) 385-389. 【18】H. Daiguji, Y. Oka, T. Adachi, K. Shirono, Theoretical study on the efficiency of nanofluidic batteries, Electrochemistry Communica- tions 8 (2006) 1796-1800. 【19】G. Karimi, X. Li, Electroosmotic flow through polymer electrolyte membranes in PEM fuel cells, Journal of Power Sources 140 (2005) 1-11. 【20】S. Levine, J.R. Marriott, G. Neale, N. Epstein, Theory of electro- kinetic flow in fine cylindrical capillaries at high zeta potentials, Journal of Colloid Interface 52 (1975) 136. 【21】J.H. Masliyah, Electrokinetic transport phenolmena, AOSTRA Technical Publication Series No. 12, AOSTRA, Edmonton, 1994. 【22】R. Magargle, J.F Hoburg, T. Mukherjee, A simple description of turn-induced transverse field dispersion in microfluidic channels for system-level design, Nanotecnology 1 (2003) 214-217. 【23】Y.T. Zhang, H. Chen, I. Mezic, C.D. Meinhart, L. Petzold, N.C. MacDonald, SOI processing of a ring electrokinetic chaotic micro mixer, University of California, Santa Babra, Engineering 2, Room 2145, CA, 93106, USA. 【24】Y. Zhang, R.W. Barber, D.R. Emerson, Creeping electro-osmotic flow through micro-channels, Proc.13th Micro-Mechanics Europe Workshop (MME02), Romania, October 2002, pp. 153-156
本研究以數值模擬,探討在有限長度之奈米尺度帶電圓管內之電解質、外加壓力驅動、流動電位、流動電流及能量轉換機制等現象。計算之空間除奈米圓管外,亦包括連接奈米圓管之入出口電解液儲槽。在數值模式中,基本假設流體為一連續流體,且充滿對稱單價之電解液。根據這些假設,針對具有電場效應之流體流動、離子傳輸,以及流場電位分佈等方程式,在適當之邊界條件下進行求解,並探討離子濃度、圓管尺度、壁面電荷密度,以及驅動壓力等對流動電位之影響。計算所得之結果顯示,離子濃度與圓管尺度之影響,可由無因次Debye length (κa)代表。在固定壁面電荷密度及驅動壓力下,流動電位隨κa之變化趨勢中,會出現一極大值,此極大值與κa間之關係,隨壁面電荷密度增加而增加。而在固定κa值及驅動壓力下,流動電位隨壁面電荷密度增加而呈現一非線性的增加。此外,在固定κa值及壁面電荷密度下,流動電位隨外加驅動力呈線性的增加。由能量轉換之觀察出發,流動電位可視為將壓力轉換為電能的一種現象。當外加負載加諸於上述之裝置時,藉由調整負載之大小,可求得流經負載之電流與負載之電位差,並藉此探討能量轉換效率。本研究之結果發現,能量轉換效率之最大值,發生於負載電位差約為最大流動電位差之一半時。此外,最大能量轉換效率隨κa改變時,可發現一極值,此極值之大小,及κa值發生處,隨壁面電荷密度之增加而增加。

In this study, the phenomena of streaming potential, streaming current and energy conversion in a pressure-driven aqueous electrolyte flow is numerically investigated. The computation domain includes a finite-length electrically charged capillary tube having diameter in nanoscale range and the reservoirs connecting at the ends of the tube. The basic assumption of the simulation is that the fluid is in continuum regime as it is in nanoscale domain. Based on this assumption, the governing equations subject to appropriate boundary conditions to be solved are the modified Navier-Stokes equation in which the electrokinetic effect is included, the electrical potential distribution in the flow filed and the ionic transport equations.
The results of numerical simulation indicate that the size and electrolyte bulk concentration effect on the streaming potential and streaming current can be represented by the dimensionless Debye length (denoted as κa in this study). Under the conditions of fixed surface charge density and driven pressure drop, it is found that a maximum value of streaming potential appears when the relation between the streaming potential and κa is examined. The value of κa where maximum streaming potential occurs depends on the magnitude of surface charge density. In the case of fixing the driven pressure drop and κa value, it is found that the streaming potential increase nonlinearly with the increase of surface charge density. For fixing the κa and surface charge density, the streaming potential increases with the increase of externally applied driven pressure drop.
In the energy conversion, an externally load is added to the system. By varying the load, it is able to compute the energy conversion efficiency from the electric power. It is found that maximum conversion efficiency occurs as the streaming potential drops to half of the streaming potential without adding the external load. It is also found that the value of maximum energy conversion efficiency depends on the values of κa and surface charge density.
其他識別: U0005-2507200713220100
Appears in Collections:機械工程學系所

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