臺灣博碩士論文加值系統

本論文為研究複合型、三角翼型、百葉窗型、平板型及裂口型散熱鰭片的熱流性能。比較鰭片的熱傳性能和鰭片間距效應的關聯性。測試的結果指出增強型鰭片如百葉窗型鰭片操作在較高的正向速度與較大的鰭片間距之條件下其性能優於平板型鰭片。結果也發現，百葉窗型鰭片的熱傳性能更勝於其它型式的鰭片，但伴隨著較高的壓降。測試的結果也顯示熱傳性能在較低的雷諾數或較小的鰭片間距下，將會有明顯地降低；亦即所謂的“最大值”庫爾本因子的現象。此現象可應用至所有的鰭片型式。藉由仔細地檢查測試結果，可斷定此現象關係著發展中與完全發展流的特性。事實上，最大值約發生在Gz=10，此值可區分流體為完全發展流或為發展流。為了得知所測試的鰭片之熱傳性能，將採用VG-1及FG-3兩種法則作爲評估。

This study presents the thermal-hydraulic performance of heat sinks having complex, delta wing, louver, plain, and slit fin patterns. Comparison of the associated heat transfer performance and the effect of fin pitch are made. Test results indicate that the enhanced fin pattern, like louver fin, is preferable to the plain fin geometry when operating at a higher frontal velocity or at a larger fin pitch. It is also found that the heat transfer performance of louver fins is better than that of other fins at the expense of higher pressure drops. Test results also reveal a significant drop of heat transfer performance at a lower Reynolds number, or at a smaller fin pitch, or the so-called “maximum” phenomenon of Colburn factor. This is applicable to all the tested geometries. By carefully examining the test results, we conclude that this phenomenon is related to the developing/fully developed flow characteristics. In fact, the maximum point occurs roughly at Gz=10 where fully developed and developing flows are separated. For performance evaluation of the tested heat sinks, comparisons are made subject to the VG-1 and FG-3 criteria.

摘 要 i
ABSTRACT ii
誌 謝 iii
目 錄 iv
表 目 錄 xv
圖 目 錄 xvii
符 號 說 明 xix
第一章 緒 論 1
1-1 研究的動機與目的 1
1-2 文獻回顧 4
第二章 實驗的設備、方法與步驟 6
2-1 實驗設備 6
2-1-1 風洞量測系統 6
2-1-2 風量供應系統 7
2-1-3 壓力量測系統 7
2-1-4 溫度量測系統 7
2-1-5 熱源供應系統 7
2-1-6 壓力扣具系統 7
2-1-7 資料擷取系統 8
2-2 鰭片散熱座的製作 8
2-3 實驗方法與規劃 9
2-4 實驗步驟 10
第三章 實驗的分析、結果與討論 11
3-1 實驗分析 11
3-1-1 熱阻的計算 11
3-1-2 壓降的計算 12
3-1-3 泵抽功率的計算 15
3-1-4 熱傳係數的計算 16
3-1-5 無因次群 16
3-2 熱交換器之性能評價的方法 17
3-3 實驗結果與討論 20
3-3-1 各種鰭片型式在相同鰭片間距下之性能分析 26
3-3-1-1 鰭片間距為1.00㎜之性能分析 26
3-3-1-2 鰭片間距為1.85㎜之性能分析 32
3-3-1-3 鰭片間距為2.63㎜之性能分析 38
3-3-2 各種鰭片型式之性能分析 44
3-3-2-1 正向風速與熱阻的關係 44
3-3-2-2 正向風速與壓降的關係 47
3-3-2-3 正向風速與泵抽功率的關係 50
3-3-2-4 正向風速與熱傳係數的關係 51
3-3-2-5 雷諾數與凡寧摩擦因子的關係 56
3-3-2-6 雷諾數與庫爾本因子的關係 58
3-3-2-7 性能評價方法~VG-1法則 61
3-3-2-8 性能評價方法~FG-3法則 63
第四章 結 論 66
參 考 文 獻 67

1.Kakac, S. and Liu, H., Heat Exchangers: Selection, Rating, and Thermal Design, 2nd ed., CRC Press, Boca Raton, 2002.
2.Incropera, F. P. and DeWitt, D. P., Fundamentals of Heat and Mass Transfer, 5th ed., John Wiley & Sons, New York, 2002.
3.Bejan, A., Heat Transfer, John Wiley & Sons, New York, 1993.
4.王啟川，熱交換設計(Ι)，二版，五南出版社，台北，民國九十二年。
5.Rich, D. G., “The Effect of Fin Spacing on the Heat Transfer and Friction Performance of Multi-Row, Smooth Plate Fin-and-Tube Heat Exchangers,” ASHRAE Transactions, Vol. 79, No. 2, pp. 135-145, 1973.
6.Rich, D. G., “The Effect of the Number of Tubes Rows on Heat Transfer Performance of Smooth Plate Fin-and-Tube Heat Exchangers,” ASHRAE Transactions, Vol. 81, No. 1, pp. 307-317, 1975.
7.C. C. Wang, et al., “A comparative study of compact enhanced fin-and-tube heat exchangers,” International Journal of Heat and Mass Transfer, Vol. 44, pp. 3565-3573, 2001.
8.Y. J. Chang, et al., “A generalized friction correlation for louver fin geometry,” International Journal of Heat and Mass Transfer, Vol. 43, pp. 2237-2243, 2000.
9.Y. J., Chang and C. C., Wang, “A generalized heat transfer correlation for louver fin geometry,” International Journal of Heat and Mass Transfer. Vol. 40, No.3, pp. 533-544, 1997.
10.M. H., Kim and Bullard, C. W., “Air-side thermal hydraulic performance of multi-louvered fin aluminum heat exchangers,” International Journal of Refrigeration, Vol. 25, pp. 390-400, 2002.
11.Springer, M. E. and Thole, K. A., “Entry region of louvered fin heat exchangers,” Experimental Thermal and Fluid Science, Vol. 19, pp. 223-232, 1999.
12.American Society of Heating, Refrigerating and Air-Conditioning Engineers, ASHRAE, Atlanta, 1993.
13.Kays, W. M. and London, A. L., Compact Heat Exchangers, 3rd ed., McGraw-Hill, New York, 1984.
14.Webb, R. L., Principles of Enhanced Heat Transfer, John Wiley & Sons, New York, 1994.
15.Kays, W. M. and Crawford, M. E., Convective Heat and Mass Transfer, 3rd ed., McGraw-Hill, New York, 1993.