跳到主要內容

臺灣博碩士論文加值系統

(35.172.136.29) 您好!臺灣時間:2021/08/02 18:36
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

我願授權國圖
: 
twitterline
研究生:黃証堅
研究生(外文):Chen-Chien Huamg
論文名稱:乙醇-二氧化碳於非均勻截面積微流道之雙相流及其在微型DMFC應用的探討
論文名稱(外文):Two-Phase Flow of Ethanol and Carbon Dioxide in Microchannels with Non-uniform Cross-section and its Application in Micro Direct Methanol Fuel Cell
指導教授:潘欽
指導教授(外文):Chin Pan
學位類別:碩士
校院名稱:國立清華大學
系所名稱:工程與系統科學系
學門:工程學門
學類:核子工程學類
論文種類:學術論文
論文出版年:2004
畢業學年度:92
語文別:中文
論文頁數:126
中文關鍵詞:雙相流非均勻截面積微流道
外文關鍵詞:two-phase flowMicrochannels with Non-uniform Cross-section
相關次數:
  • 被引用被引用:0
  • 點閱點閱:97
  • 評分評分:
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
微流道氣-液雙相流的現象探討是極有趣且深奧的課題,不僅可建立微小尺度下雙相流物理機制資料之外,也可以提供微電子散熱系統、微熱交換器設計等重要參考依據。且最近引人注目微型燃料電池,其陰極、陽極流道中雙相流現象亦是研究要项之一。

本研究以乙醇與二氧化碳於非均勻截面積微流道探討甲醇燃料電池觸媒層反應後於流道中所形成的氣-液雙相流現象。本研究應用微機電(MEMS)的體型微加工技術,於矽質基板上完成不同結構的漸縮與漸擴微流道,其寬度變化分別為1575μm線性漸縮至45μm、35μm線性漸擴至1475μm,流道深度可分別為69.5μm與59.6μm。藉由控制乙醇與二氧化碳質量流率,量測流道進出口端的壓力並以高速攝影機觀察雙相流動現象。本研究液體流量範圍為3.18×10-9 m3/s ~ 1.638×10-8 m3/s,氣體流量範圍為1.5×10-8 m3/s ~ 1.8×10-7 m3/s。

研究結果顯示單相液體實驗的最高流量時,漸縮管的壓降較漸擴管高38.8 kPa,主要是漸縮管流體流動是加速過程而漸擴管卻是減速過程,導致漸縮管單相壓降大於漸擴管壓降。漸縮管雙相壓降變化的幅度與氣、液體積流率的變化約呈線性關係。在固定液體流量的條件下最高氣體流量及最低氣體流量之間雙相流壓降變化,在本研究之氣-液體流量範圍內,雙相壓降變化約略呈定值。相反地,在漸擴管中雙相壓降變化趨勢並不會隨著氣體流量的增加而上升,而是幾近平坦的曲線變化,甚至於高氣體流量時因為加速度壓降的效應使得壓降有減少的趨勢,並非如傳統管徑或圓管及方形管雙相壓降會隨質量流率增加而增加。因此,本研究認為漸擴流道的設計較能應用於直接甲醇燃料電池陽極流道。

本實驗發現流道結構對雙相流動型態的影響極為顯著。漸縮管的雙相流並沒有觀察到氣泡流而是以彈狀流居多。於漸縮管近進口端會因氣體的慣性力而形成分層流,攪拌流主要發生於長彈狀氣泡與短彈狀氣泡之間的碰撞接合點所產生的扭轉、波動現象;高氣體流量下在流道近出口端會有環狀流出現。本研究在漸擴管中觀察到的流譜包括:磨菇狀氣泡流、短彈狀流、長彈狀流、接合攪拌流、及出口處彈狀氣泡前緣會變成尖端形的流譜,且因為流道截面積逐漸變大則沒觀察到穩定的環狀流。
This present work investigates experimentally the two-phase flow of ethanol and carbon dioxide in non-uniform microchannels to simulate the two-phase flow phenomenon on the flow channel of a micro direct methanol fuel cell in which CO2 bubble may regenerated due to methanol oxidation. The diverging and converging microchannels are fabricated in silicon wafer by bulk micromachining, and channel width a varied linearly was from 1575μm to 45μm for a converging channel, and from 35μm to 1475μm for a diverging one, while the channel depth is 69.5μm and 59.6μm for both channel. The volume flow rates of ethanol and carbon dioxide are controlled range from3.18×10-9m3/s to 1.638×10-8m3/s and from 1.5×10-8m3/s to 1.8×10-7m3/s,respectively. Single phase liquid flow and two-phase flow pressure drop through both types of channels are measured. Moreover, a high speed video camera is employed to capture two-phase flow pattern in both diverging and converging microchannels.

The single phase liquid experiment, results investigate that the pressure drop of converging microchannels is 38.8 kPa higher than diverging microchannels at the largest liquid flow rate. The main reason may be an accelerated low in converging microchannels but a decelerated flow in diverging microchannels. In addition, two-phase pressure drop in the converging microchannel is found to be proportional to the gas at a given liquid volume flow rates. In diverging microchannels, the two-phase pressure drop hardly increases with the gas volume flow rate at a given liquid flow rate.

In this study, the structure of microchannels influences two-phase flow patterns significantly. Several peculiar flow patterns are observed in converging micro-channel, including long and short slug flow, wavy flow, churn flow and annular flow. In diverging microchannels, mushrooms bubble flow, slug flow and merging churn flow, chestnut slug flow (a slug flow with sharp head bubble), are also observed except stable annular flow.
參考文獻
1. 郭品璽,“新世代能源技術-燃料電池”,化工技術,第十卷第六期,pp.121~131,(2002)
2. 林有銘,“氫氣燃料電池技術”,化工技術,第七卷,第十期,pp.164~171,(1999)
3. .A. Kawahara , M. Sadatomi ,K. Okayama ,M. Kawaji,2003“Effect of Liquid properties on pressure drop of Two-Phase Gas-Liquid flow Through a Microchannel ”, First International Conference on Microchannels and Minichannels, pp.479~486

4. M. Kawaji, P.M.-Y.Chang, 2003“Unique characteristics of adabatic Gas-Liquid Flow in Microchannel Diameter and Shape effects on Flow patterns”, First International Conference on Microchannels and Minichannels, pp.115~227

5. A. Kawahara , P.M-Y. Chung , M. Kawaji , 2002,“Investigation of two phase flow pattern void fraction and pressure drop in a Microchannel”,International Journal of Multiphase Flow, Vol. 28 , pp.1411-1435

6. Akimi Serizawa ,Ziping Feng ,Zensaku Kawara, 2002,“Two-phase flow in microchannel”,Experimental Thermal and Fluid Science ,Vol. 26, pp.703-714

7. T.S Zhao , Q.C. Bi , 2001,“Pressure drop characteristics of gas-liquid two- phase flow in vertical miniature triangular channels ”,International Journal of Heat and Mass Transfer ,Vol.44 pp.2523-2534

8. T.S Zhao , Q.C. Bi , 2001, “Co-current air-water Two-phase flow patterns in vertical triangular Microchannels”, International Journal of Multiphase Flow ,Vol.27, pp.765-782

9. K.A. Triplett , S.M. Ghiaasiaan , S.I. Abdel-Khalik , D.L. Sadowski,1999,“Gas-liquid two-phase flow in microchannels ,PartⅠ:two-phase flow patterns”,International Journal of Multiphase Flow, Vol. 25,377-394

10. K.A. Triplett , S.M. Ghiaasiaan , S.I. Abdel-Khalik , D.L. Sadowski,1999,“Gas-liquid two-phase flow in microchannels ,PartⅡ:void fraction and pressure drop”,International Journal of Multiphase Flow, Vol. 25 , 395-410

11. K.Mishima, T. Hibiki , 1996, “Some charactistics of air-water two–phase flow in small diameter vertical tubes ”, International Journal of Multiphase Flow, Vol. 22, No.4,pp.703~712

12. Han Ju Lee , Sang Yong Lee,2001,“Pressure drop correlations for two-phase flow within horizontal rectangular channels with small heights”, International Journal of Multiphase Flow, Vol. 27 ,pp.783~796

13. Guoqiang Lu and C. Y. Wang ,2003 “Two-Phase Microfluidic Visualization in a Direct Methanol Fuel Cell ”, The Electrochemical Society, Inc

14. K. Soctt, W.M. Taama, P. Argyropulos , 1998“Material aspects of liquid feed direct methanol fuel cells”, Journal of Applied Electrochemistry ,Vol.28 , pp.1389~1397

15. P. Argyropulos ,K. Soctt ,W.M. Taama, 1999,“Carbon dioxide evolution patterns in direct methanol fuel cells”,Electrochimica Acta ,Vol.44 , pp.3575~3584

16. P. Argyropulos ,K. Soctt ,W.M. Taama, 1999,“Gas evolution and power performance in direct methanol fuel cells”, Journal of Applied Electrochemistry ,Vol.29 , pp.661~669

17. K. Soctt, P. Argyropulos ,P.Yiannopoukos, W.M. Taama, 2001 “Electrochemical and gas evolution characteristics of direct methanol fuel cells with stainless steel mesh flow beds ”,Journal of Applied Electrochemistry ,Vol.31 , pp.823~832

18. K. Soctt, W.M. Taama , 1998“Performance of a direct methanol fuel cell”, Journal of Applied Electrochemistry ,Vol.28 , pp.289~297

19. K. Soctt, P. Argyropulos ,P.Yiannopoukos,1999,“A model for the liquid feed direct methanol fuel cell ”, Journal of Applied Electroanalytical Chemistry ,477 , pp.97~110

20. W.L Chen , M.C. Twu, C. Pan ,2002,“Gas-liquid two-phase flow in micro-channels”,International Journal of Multiphase Flow ,28, pp.1235~1247

21. Man Lee, Yiu Yan Wong ,Man Wong and Yitshak Zohar,2003“ Size and shape effects on two-phase flow patterns in microchannel forced convection boiling”,Journal of Micromechanic and Microengineering , 13, pp.155~164

22. Shikida, Mituhiro ,Sato ,Kazuo ,Tokoro, Kenji and Uchikawa , Daisuke, 2000“Differences in anisotropic etching properties of KOH and TMAH solution”,Sensors and Actuators, Vol.80 ,pp.179~188

23. C-H Lin ,G-B Lee ,B-W Chang ,G-L Chang ,2002,“A new fabrication process for ultra-thick microfluidic microstructures utilizing SU-8 photoresist ”, Journal of Micromechanic and Microengineering , 12, pp.590~597

24. Sheng Li, Carl B Freidhoff , Robert M Young and Reza Ghodssi1, 2003, “Fabrication of micronozzles using low-temperature wafer-level bonding with SU-8” , Journal of Micromechanic and Microengineering , 13, pp.732~738

25. Marc J. Madou , Fundamentals of MICROFABRICATION : the science of miniaturization , Second Edition , (2002)

26. WWW Website:http://www.microchem.com

27. G. Q.Lua ,C.Y. Wang, T.J. Yen, X. Zhang ,2004“Development and characterization of a silicon-based micro direct methanol fuel cell”, Electrochimica Acta , 49, pp821~828

28. 潘欽,“沸騰熱傳與雙相流” ,國立編譯管館,台灣,2001
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top