李雨臺灣大學：應用力學研究所葉祐銘Yeh, Yu-MingYu-MingYeh2007-11-292018-06-282007-11-292018-06-282007http://ntur.lib.ntu.edu.tw//handle/246246/62375本文所探討之旅波介電泳幫浦基本上為一矩形截面的直微流道，在其一或二個相對壁面上建置有如鐵軌枕木般的平行微電極陣列，在每一電極上施予適當相位的交流電，可對流道中電中性微粒(如血球)產生旅波介電泳力，驅使其移動，並透過黏滯阻力，拖曳其週遭流體，而達到幫浦的輸送功能。本文針對此一幫浦，共完成了如下工作：(1) 電場分析是本文的第一步，針對電場本文完成了一以傅立葉級數來表示的分析解及數值解計算程式，可快速了解不同電極設計的電場變化。(2) 當幫浦的操作頻率飄離最佳設計頻率(CM因子實數部份為零的頻率)，傳統負介電泳力會對進入電極上方區域前的微粒施予一與旅波介電泳力相反之力，阻礙其進入而使幫浦效能降低，甚或使之失效，而為設計高效能旅波介電泳幫浦首要克服者，經由分析及計算，本文提出一項有效的解決辦法，乃是在電極區進口處加進兩片"輔助電極"，相位分別為90∘, 270∘或180∘, 270∘，並把施加在輔助電極上電壓值適度降低，就測試案例，可使原本流道出口平均流速由100μm/s，增加到160μm/s，增加率為60%。(3) 上述幫浦輸送效能的評估及計算須藉助含電場的二相懸浮流的計算，本文修改前人計算程式使包含懸浮微粒對微粒週遭流體電性的影響，並對不同幫浦參數進行數值模擬。在長流道(3000µm)的模擬，輔助電極協助下，施加電壓6V，頻率10MHz，其流道上壁面的微粒x方向平均速度為13.46 µm/s，而陳銘昌(2007)的實驗結果為15 µm/s，二者差異約10%。總括而言，旅波介電泳幫浦為一項有效傳輸二相懸浮流(如血液)的微幫浦，本研究有助提昇該幫浦的分析及設計能力。The traveling wave dielectrophoretic pump studied in this thesis is essentially a straight micro channel with electrode array(s) built on one or two of its walls. A traveling wave electric field is generated inside the channel when an ac field is applied to the electrodes with suitable phase shift between neighboring electrodes. A generalized dielectrophoretic force, including both the traditional and traveling wave dielectrophoretic force, is imparted on the suspended dielectric particles in fluid (such as our cells in blood) inside the channel. Under suitable conditions, the particles move along the channel. As the particles move, they drag their neighboring fluid, and thus the whole medium is delivered (the two phase suspension medium is being pumped). This goal of this thesis is to study such a pump, and several works were completed. (1) The electric fields for different electrode arrangements have been solved via analytical and numerical method. (2) When the pump is operated at frequency shifted from its optimized design frequency (when the real part of the Clausius-Mossotti factor equals zero), the traditional dielectrophoretic force will exert a force to the particles, which is opposite to the driving traveling dielectrophoretic force, when they entered the region above the electrode region. Such opposite force slows down the particles which degrade the pumping efficiency, or even blocks the particles which make the pump fails. In order to overcome such a drawback, a remedy is proposed, which is to add two assistant electrodes before the electrode array. When the assistant electrodes are operated at phase 90 and 270 or 180 and 270 (0 for the first electrode of the array) at a suitable voltage less than that of the electrode array, the opposite traditional dielectrophoretic force can be reduced. Also the pumping efficiency is enhanced with the assistant electrodes. At optimized design frequency, the average velocities of particles at the pump exit are 100 micron/s and 160 micron/s, respectively, for a typical case without and with assistant electrodes. (3) Calculation of two-phase suspension flow under the electric field is required for studying the pumping efficiency. We have updated an existing computer program by modifying the boundary conditions for particle impact and including variable electric properties and of the fluid, which are crucial for a correct simulation. For a typical case with assistant electrode, the numerical average velocity of the particles at exit accounting for the variable electric properties is 13.46 micron/s, which is about 10% less than the corresponding experimental result, 15 micron/s.誌謝 i 中文摘要 ii 英文摘要 iii 目錄 v 圖表目錄 vii 符號說明 xiii 第一章 導論 1 1.1 研究背景 1 1.2 旅波介電泳幫浦及其原理 2 1.3 研究動機 4 1.4 文獻回顧 5 1.5 本文架構 8 第二章 理論模式 9 2.1 電場模式 9 2.2 介電泳作用力理論 13 2.3 微粒與流體之雙向耦合 20 2.4 旅波介電泳幫浦設計分析 22 第三章 數值方法 25 3.1 電場計算 25 3.2 流場計算 26 3.3 微粒運動方程式 34 3.4 流場與微粒之雙向耦合 35 3.5 邊界條件設定 36 第四章 結果與討論 38 4.1 格點測試與程式驗證 38 4.2 傅立葉級數電場分析 41 4.3 旅波介電泳幫浦：介電泳力的分析 53 4.4 旅波介電泳幫浦：輸送效能分析 60 4.5 長流道旅波介電泳幫浦的模擬 66 第五章 結論與未來展望 68 5.1 結論 68 5.2 未來工作 69 參考文獻 70 附圖表 7410667976 bytesapplication/pdfen-US旅波介電電泳幫浦效能traveling wavedielectrophoresispump performancethesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/62375/1/ntu-96-R94543062-1.pdf