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題名 | 板鰭片有限熱導度對板鰭管式熱交換器三維熱流場之影響=Numerical Solution to the Conjugate Heat Transfer Problem of Flow Past a Finned-Tube Heat Exchanger |
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作者姓名(中文) | 張文政; 林志浩; | 書刊名 | 力學 |
卷期 | 15:2 1999.12[民88.12] |
頁次 | 頁137-145 |
分類號 | 460.027 |
關鍵詞 | 鰭片; 熱交換器; 共軛熱傳; Fin; Heat exchangers; Conjugate heat transfer; |
語文 | 中文(Chinese) |
中文摘要 | 本文以數值方法探討工業上常用之板鰭管式熱交換器(正三角形交錯排列的四排 圓管,直徑為5/8"圓管,38mm管間距,8 fins/in鰭片間距,鋁材質鰭片,0.25mm鰭片厚 度,雷諾數Re□=400時)板鰭片有限熱導度對板鰭管式熱交換器性能之影響;亦即實際考慮 板鰭片溫度是不知道,以及存在鰭片厚度之情況下,探討兩水平鰭片間置放四根已知溫度的 垂直圓管的通道內三維熱流場之共軛熱傳問題。由數值結果顯示:非等溫鰭片(有限熱導度) 之局部及整體的熱傳係數和等溫鰭片(無限熱導度)之結果在定性上很相似,但等溫鰭片下所 得熱傳的量約大於非等溫鰭片時25%。至於鰭片上溫度的分佈,非等溫鰭片的結果與等溫鰭 片的結果,有很大的差異。因此以前的研究者假設鰭片為等溫的條件所得的結果將產生不小 的誤差。 |
英文摘要 | Numerical methods are performed to evaluate the effects on the performance of the generally-applied industrial finned-tube heat exchanger with finite thermal conductivity. The three dimensiomal conjugate heat transfer in a duct, in which four rows tubes with known temperature are placed vertically, is studied considering the temperature and thickness of the fin is unknown and fixed respectively. From this are obtained the more accurate temperature distribution of the fin, and temperature and pressure distributions inside the duct. Computation results show that under the generally-applied industrial specification, the local and bulk heat transfer coefficients of the non-isothermal fins (finite thermal conductivity) present similarity qualitatively to those of isothermal ones (infinite thermal conductivity), but the heat transfer capacity obtained with the isothermal fins is 25% greater than that with non-isothermal ones. As for the distributions of the temperature, results with non-isothermal fins differ greatly from those with isothermal ones both qualitatively and quantitatively. It is therefore concluded that the results from former researches assuming constant fin temperature may produce much error. |
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