冷冻油含量对满液式蒸发器热传特性影响之研究-台湾区冷冻空调工程.PDF

冷凍油含量對滿液式蒸發器熱傳特性影響之研究 Influence of Refrigerant Oil Concentration on Heat Transfer Characteristics of Flooded Evaporators *1 *2 *3 *4 李宗興 林佳泯 蔣國雄 傅彥鈞 T.S. Lee, C.M. Lin, K.S. Chiang, M.Y. Lee *1 國立台北科技大學冷凍空調工程系副教授 *2 國立台北科技大學冷凍空調工程系碩士班研究生 摘 要 本文主要目的是利用理論模擬配合實驗驗證的方 法研，究冷 媒中冷凍油含量對 於滿液式蒸發器 在 滿載運轉條件 下熱傳 特性之影響 。蒸發器內 殼側沸騰熱傳模 式係採用疊 加法與漸進線法 ，而核沸騰熱 傳則採用 Cooper 與 Gorenflo所提 出之經驗式 。除了探討各熱傳經驗 式之適用性外，模擬結果並 與公 稱能 力 120RT ，R-134a 冷媒 、三迴路殼管滿液式 蒸發器之螺旋式冰水機 組做驗證 。研 究結果顯 示 ：冰 水 主機滿載運轉時 ，採用疊加法與 Gorenflo 之預測模式所得 結果與實驗值較為吻合 ；另外由參數分析 可 知：當冷凍油含量由 0 至 5%變化時 ，平均每增加 1% ，將使冷凍能力降低約 5.4%。 關鍵詞 ：滿液式蒸發器、對流沸騰、冰水機組、理論模擬 ABSTRACT In this article, the influence of concentration of refrigerant oil on heat transfer characteristics of flooded evaporators during full-load operation has been studied theoretically and experimentally. The nucleate pool boiling heat transfer coefficient is calculated by Cooper ’s or by Gorenflo’s correlations, while the boiling heat transfer of shell-side is determined by superposition or asymptotic models. A comparison of various combinations, to estimate the heat transfer coefficient of nucleate pool boiling and convective boiling, are presented. The predicted results are compared with experimental data on an R-134a, three-pass, and shell-and-tube flooded type evaporators. The result shows that: the model combined by superposition model and Gorenflo correlation has a good agreement with experimental data. Effect of oil concentration on heat transfer performa