https://scholars.lib.ntu.edu.tw/handle/123456789/59996
標題: | Forced convective heat transfer of 45° rib-roughened fin flows | 作者: | Chiang, K.F. Chiang K.F. Chang S.W. Chang, S.W. Chen P.-H. Chen, P.H. |
關鍵字: | Skewed;Rib-roughened;Fin-flow | 公開日期: | 2005 | 起(迄)頁: | 743-754 | 來源出版物: | Experimental Thermal & Fluid Science 29 | 摘要: | The detailed heat transfer measurements in three side-open & bottom-sealed rectangular channels with two opposite walls roughened by 45° full staggered ribs were performed using the infrared radiometer. The present flow configuration simulated an enhanced coolant channel of the fin-type heat-sinks for cooling of electronic chipsets. The hydraulic diameter of three test channels was 14.8 mm with different length-to-gap (L/B) ratios of 21.33, 17.11 & 13.56. The influences of L/B ratio on the local & spatially averaged heat transfers over the rib-roughened surface at Reynolds numbers (Re) of 500, 1000, 2000, 3000 & 3300 were examined. A selection of heat transfer results illustrated the interactive effects between the side-profile leakage-flow & the rib-induced flow phenomena, which were L/B ratio dependent. Heat transfer levels over the rib-roughened surface consistently increased with the increase of Reynolds number or the decrease of L/B ratio. The skewed streamwise ‘‘saw-tooth’’ heat transfer variations gradually emerged over the rib-roughened surface when the Reynolds number systematically increased. Comparing with the heat transfers in the likewise channels but roughened by 90° staggered ribs, the 45° staggered ribs could further enhance heat transfers over 10% for L/B = 21.33 & 50% for L/B = 13.56. Heat transfer correlation for the spatially averaged Nusselt number over a rib-roughened fin surface was generated using Re & L/B ratio as the controlling parameters. A criterion for determining the optimal L/B ratio that could provide the maximum cooling power over a rib-roughened fin surface was subsequently derived to aid the design tools for the heat-sink selection. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/2006111501254314 | 其他識別: | 246246/2006111501254314 |
顯示於: | 機械工程學系 |
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