摘 要

　　本論文總共分為2個部分，第一部分乃使用吸入型開放式風洞測試系統，配合一套環境控制設備，使測試環境溫度保持在27oC左右，相對濕度保持70%以下，在此環境控制下，針對交錯排列橢圓鰭管式熱交換器之測試本體，其長短軸分別為2.5、2.83及3.1分別進行乾盤管及濕盤管之性能測試實驗，在乾盤管實驗中，管側內之工作流體為熱水(80oC)，而鰭片側之工作流體為空氣。在濕盤管實驗中，亦藉由管側內工作流體為熱水，鰭片側工作流體為空氣的方式，並在空氣入口處施予噴霧效應，噴霧量(kg H2O/kg Air)分別為0.05％、0.1％、0.15％及0.2％，分別找出其熱傳量、熱傳係數、熱傳因子、壓降與摩擦因子之變化。第二部分在開發一套鰭管式熱交換器之電腦輔助設計軟體。

　　本文在實驗中除了改變熱交換器鰭片長短軸比之外，另外施加不同噴霧量予以探討。從乾盤管實驗結果看出橢圓鰭片長短軸比為2.5時，其熱傳效果較長短軸比為2.83、3.1好。但長短軸比為2.5其壓降亦為最大。而從濕盤管實驗中，亦即施加噴霧效應後，當長短軸比為3.1時其熱傳量增加百分比較長短軸比為2.5及2.83高。而當施加噴霧效應後，平均熱傳量提升約為10~55%。

　　鰭管式熱交換器電腦輔助分析及設計軟體部分，係以Visual Basic 6.0程式語言撰寫一套適用於個人電腦使用交談式之電腦輔助設計軟體。 而電腦輔助設計軟體具有以下兩種功能：
(1) 性能評估(Rating Problem)：使用者輸入一氣冷式蒸汽冷凝器的實際尺寸，管側蒸汽及鰭片空氣之流量，進口溫度和壓力，以及噴霧量，則可求出管側蒸汽冷凝量（熱傳量）及空氣的出口溫度，濕度，及兩側壓力降。
(2) 尺寸計算(Sizing Problem)：當告知兩側流體的流量，進出口溫度（熱傳量）及容許壓力降，則可計算出氣冷式蒸汽冷凝器的熱傳面積（包括鰭管長，鰭管數，鰭片間距等）及所需噴霧量等。

ABSTRACT

　The paper was divided into two parts . First ,an induced open wind tunnel was used to measure the thermal-hydraulic characteristics with and without spray effect .The dimensions of heat exchangers for elliptic finned tube are 2.5,2.83 and 3.1 for the aspect ratio. The ambient temperature and humidity were controlled at about 27oC and 70% , respectively. The range of the frontal velocity for measurement was controlled between 1 m/s to 5 m/s, while the water inlet temperature and flow rate are maintained at 80oC and 1100 L/hr. The ratio of the spray amount compared with the air flow rate were controlled at 0.05 , 0.1 , 0.15 , 0.2 (kg water per kg dry air). The enhancement of the heat transfer and pressure drop when increasing the spray ratio is much effective for the tube aspect ratio 3.1.

　Second, an interactive computer aided design software for the air-cooled condenser was developed. It has been written by Visual basic 6.0 and can be run in any personal computer. The software has the following two functions：
(1) Predicting the performance of ACC condenser as the dimensions are given .
(2) Determine the necessary dimension of ACC condenser as given the required performance.

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