電滲泵之焦耳熱效應分析; Joule Heating Effects of Electroosmotic Pump

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Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/2961

Title:	電滲泵之焦耳熱效應分析;Joule Heating Effects of Electroosmotic Pump
Authors:	劉政廷;Jheng-ting Liou
Contributors:	機械工程研究所
Keywords:	焦耳熱效應;質子交換膜管;電滲流;電滲泵;Nafion tubing;Joule heating effect;Electroosmotic pump;Electroosmotic flow
Date:	2008-07-09
Issue Date:	2009-09-21 12:02:08 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	電滲泵目前在微流體裝置與微電子冷卻方面的應用漸增，對於其傳輸液體表現與溫度變化特性的探討將有助於提升泵的性能。本文以商用的燒結矽片作為驅動流體的多孔介質製作電滲泵，它依據電雙層(electrical double layer)效應驅動流體。本文使用不同濃度(0.5-4 mM)的硼酸鹽溶液、去離子水與氯化鉀(1 mM)溶液為工作流體並利用不同外加電壓(50-150 V)形成電場。溫度量測使用熱電偶(thermocouple)量測電滲泵出口端的溫度變化。實驗顯示當離子濃度提升與外加電壓的增強都會使得焦耳熱效應(Joule heating effect)更加明顯。鑑於電滲泵作動期間因為水溶液的電解反應在正負極端分別釋出氧氣泡與氫氣泡，本文藉由二層的質子交換膜管(Nafion tubing)套在白金電極上，來降低氣泡對流體連續傳輸的影響。經由此種改善方式，電滲泵可連續作動8小時且流率相當穩定。本文也以自製的燒結矽片作為多孔介質測試其泵的性能，結果顯示自製燒結矽的泵性能與商用的燒結矽的泵性能相當。 The electroosmotic pump (EOP) has been used in the microfluidic devices and in the micro-electronics cooling recently. To investigate the behavior of the transporting liquid and its temperature variation can enhance the performance of the EOP. In this study, the EOP is made from a commercial porous sintered silica frit to transport liquid, which utilizes the electric double layer effect as driving force. Three types of working fluid are tested: including the borate solution with various ranges of concentrations (0.5-4 mM), the deionized water and the potassium chloride solution (1 mM). Moderate range of voltages (50-150 V) was applied for generating electric field inside the pump. The thermocouple is used to measure the temperature variation of the outlet of the EOP. Experimental result reveals that the increases of the ionic concentration and the applied voltage will amplify the Joule heating effect. Due to the electrolysis reaction on the electrode, the hydrogen and oxygen bubbles will be generated at the anode and cathode, respectively. In order to reduce the bubbles, this study sheathes the platinum wire electrode with two layers of Nafion ion exchange membrane tubes. With this modification this EOP demonstrates continuously operate for eight hours with a stable flow rate. This study also fabricate a frit with self-made the porous sintered silica; its result reveals that the performance of self-made porous frit was comparable to that of the commercial frit.
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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