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標題: 一種渦捲型式熱交換器之熱傳性能之探討
Heat Transfer Performance of a Spiral Heat Exchanger
作者: 沈君洋
關鍵字: 能源工程;應用研究;spiral heat exchanger;effectiveness;second law of thermodynamics;exergy recovery index
This work intends to investigate the heat transfer and exergy transfer performance of aspiral heat exchanger. The structure of the heat exchanger is composed of two spirals ofArchimedes. The spiral heat exchanger possesses some advantages over most of commercialheat exchangers. For instances, in a limited space, it can provide a larger heat transfer area.Its flow pattern can be arranged to be counter-flow, thus the heat transfer is more effective.Its two streams flow between two spirals, due to flow disturbance, a larger convective heattransfer coefficient between the flow and solid wall can be achieved. Consequently, theoverall heat transfer coefficient of the heat exchanger is also larger. In addition, the heatexchange can be made of stainless steel. Hence, for recovering waste heat from flue gases, itdoes not have corrosion problem.In this work, a mathematical model will be used to analyze the heat transfer in thespiral heat exchanger. The temperature distributions of the two flows will be solved using anumerical method and the result will yield the ε-NTU relation of the heat exchanger. Asecond-law analysis for acquiring the exergy recovery index of the heat exchanger will alsobe performed. The above ε-NTU relation and exergy recovery index are important todesigning the heat exchanger for recovering waste heat. In this work, a prototype of thespiral heat exchanger will also be made. In literature, many different designs for spiral heatexchanger can be found. Instead of following their complicated manufacturing processes,this work will adopt a rather easier process for manufacturing the prototype spiral heatexchanger. After the manufacturing of the prototype spiral heat exchanger is accomplished,its heat transfer performance will be tested.

此研究欲探討一個渦捲式熱交換器之熱能與有效功(exergy)之傳輸性能,此渦捲式熱交換器幾何結構上由兩組阿基米德渦線所組成,在有限之體積下,其可具有相當大之熱傳面積;而在此熱交換器中,兩個管道之流體其相互間之流動方向可安排為逆向(counterflow),因此與其他型式之熱交換器比較,其流體間之熱傳方式相當有效率;同時此熱交換器中之兩個流體均為沿著渦線而流動,此種流動方式會造成流體之擾動,故流體與管壁間會產生較大之熱對流係數,因此熱交換器之整體熱傳係數亦會較大。除此之外,此熱交換器可由不銹鋼製成,故於煙道廢熱之回收使用上,亦可解決耐腐蝕之問題。此研究擬採用一個數學模式對熱交換器之熱傳性能進行探討,並經由數值分析方法解答流體於管道中之溫度分佈,進而獲得熱交換器之熱效率與熱能傳輸指數之關係(ε-NTU),研究中同時擬針對此種熱交換器進行熱力學第二定律之分析,在不同操作條件下,以獲得此熱交換器之有效功回收指數(exergy recovery index),此熱效率與有效功回收指數之資訊攸關渦捲式熱交換器之設計。此研究亦擬設計與製作一個此型式之熱交換器,文獻中可以找到多種不同製造渦捲式熱交換器之方法,此研究將設計一種較為簡單之製造方式,並根據此設計之方法以完成製作一個渦捲式熱交換器,最終並進行其熱能傳輸性能之測試。
其他識別: NSC100-2221-E005-077
Appears in Collections:機械工程學系所

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