冪次型流體靜電感應泵浦之流況分析

Electrostatic Induction Pumping of Power-law Liquids

張家聞(Jia-Wen Zhang)

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(2014年)

https://doi.org/10.6342/NTU.2014.10133

摘要

流體靜電感應泵浦在這幾年來，受到眾多科學家及團隊們的關注及研究。而其中一種泵浦類型，是在1970年時由G.I Taylor首先發明，並將其取名為泰勒泵。此種靜電感應泵浦之物理模型，為一矩形槽之形式且內部放置半絕緣流體。吾人在矩形槽之兩端加裝電極並使之通電後，於液氣界面處將累積感應電荷；其中當電場施加方向平行界面時，即使得電荷受電力加速並扯動周遭流體運動達到泵浦之效果。在本文中，吾人以泰勒靜電感應泵浦為基礎架構，探討電驅動力強度、液槽之長寬比、電極位置與傾角、重力效果…等物理參數之改變，如何影響非牛頓冪次型流體於泰勒泵中之流況與流變效應。此外，吾人更引入線性那維爾滑移定律，並將滑移與無滑移條件下所解得之流場情況進行比較。本研究著重的部分在於，當吾人改變上述可調眾多變因後，將會對流場中之速度分佈、渦度分佈造成什麼變化，並了解剪應力場及壓力場在整個流場中之分佈情形。最後，吾人亦探討各物理參數之改變，對感應電荷所集中之液氣自由界面(或液面函數)將有何種影響。

關鍵字

靜電感應泵 ； 泰勒泵 ； 冪次型非牛頓流體 ； 那維爾滑移定律 ； 電動水力學

並列摘要

Electrostatic induction pumps have recently been studied and demonstrated by many groups of researchers. One type of the electrostatic induction pumps is called the Taylor pump, which is first invented by G.I Taylor in the 1970s. The physical model of Taylor’s pump includes an insulated tank, filled with low conductivity liquids, and electrodes installed at each end of the tank. When an electric potential difference is imposed between the electrodes, induced charges will accumulate at the liquid-air interface. As the direction of the electric field becomes parallel to the interface, the electric field acts upon the interfacial charges which in turn drives the liquid into motion thus providing pumping effects. In this thesis, we investigate how the physical parameters of electric field strength, aspect ratio of the tank, inclination angle of the electrode,etc. may influence the operation and liquid flow condition within the Taylor pump. In this research, we also consider the effect of gravity and employ power-law liquids as the working fluid in our analysis. Additionally, we compare the different flow situations respectively obtained by the linear Navier slip law land the no-slip boundary condition. The goal of this thesis is to investigate how changes in the above physical parameters may influence or vary the flow and rheological responses within the flow field of the Taylor pump. These flow responses are generally characterized by the velocity, vorticity, shear stress, and pressure distributions within the Taylor pump, as well by the deflection of free surface between the air and liquid phases.

並列關鍵字

Electrostatic induction pumping ； Taylor pump ； Power-law liquids ； Navier slip law ； Electrohydrodynamics

參考文獻

參考文獻

1. J.M. Crowley, The efficiency of electrohydrodynamic pumps in the attraction mode, Journal of Electrostatics. 8 (1980) 171-181.

2. R.V. Raghavan, Electrokinetic actuation of low conductivity dielectric liquids, Sensors and Actuators B. 140 (2009) 287–294.

3.T.M. Squires, S.R. Quake,Microfluidics:Fluid physics at the nanoliter scale, Reviewsof Modern Physics. 77 (2005) 977–1026.

4. Y. Feng, J. Seyed-Yagoobi, Understanding of electrohydrodynamic conduction phenomenon, Physics of Fluids 16. (2004) 2432–2441.