研究生: |
張添豪 |
---|---|
論文名稱: |
漸縮角度對微流道冷凝現象的影響研究 |
指導教授: | 潘欽 |
口試委員: | |
學位類別: |
碩士 Master |
系所名稱: |
原子科學院 - 工程與系統科學系 Department of Engineering and System Science |
論文出版年: | 2010 |
畢業學年度: | 98 |
語文別: | 中文 |
論文頁數: | 84 |
中文關鍵詞: | 微流道 、冷凝 、漸縮角 |
相關次數: | 點閱:2 下載:0 |
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本論文探討蒸汽在三種不同漸縮角度(β=0.5°、1.0°、1.5°)之微流道的冷凝現象,觀察冷凝雙相流譜並分析冷凝熱通率、局部熱傳遞係數與冷凝壓降等與蒸汽質量流率及漸縮角度的關係。
研究結果顯示,蒸汽在流道內冷凝雙相流譜可分微霧狀/環形流、注射流與彈狀/氣泡流等三種流動型態。其中注射流位置會因蒸汽質量流率的增加而延後發生。
流道的漸縮角度會影響流譜注射流的位置,連帶影響了熱傳表現。相同蒸汽質質量通率下,漸縮角度較大之流道注射流位置延後發生,霧狀環形流區域所佔流道面積比較較高,會有較高冷凝熱通率;在漸縮角度較小流道液膜較薄,有利於蒸汽潛熱的移除,因此漸縮角度較小之流道局部熱傳遞係數會高於漸縮角度大之流道。
另外,在注射流區前後流道內局部壓力變化與漸縮角度有關。相同蒸汽質量流率下,注射流區前漸縮角度小之流道寬度較小,局部壓力會高於漸縮角度較大之流道;注射流區後,漸縮角度的設計加速液體排出流道,因而漸縮角度大之流道局部壓力會高於漸縮角度小之流道。
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