Thermal characteristics of rotating pin-fin heat sinks subject to a circular impinging jet

• Main Authors: H. J. Liao, 廖宏儒
• Other Authors: S. C. Tzeng
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/74310367381895440709

碩士 === 建國科技大學 === 自動化工程系暨機電光系統研究所 === 95 === This work experimentally investigated the heat transfer enhancement of jet impingement onto the rotating Square post pins-fins heat sink. Air was used as impinging coolant, while a square pin-fin heat sink with uniformly in-line arrangement was employed. Relevant change parameters include: Heat sink quantity, jet Reynolds number (Re), the relative distance of nozzle-to-fin tip (C/d), the relative of pin-fin width and diameter of the spray nozzle (L/d), the rotational Reynolds number (Rer). The result of the experiment is probing into relevant change parameters on the dimensionless temperature distributions and the average Nusselt number were presented. The result shows in the static system. Nusselt number will rise with increase of jet Reynold number. And average Nusselt number of 9×9 heat sink is higher than 5×5 heat sink in low Reynold number. Under the same cold flowing rate of impact. Average Nusselt number of the diameter d=13 mm of the jet nozzle is 1.1~1.4 times of d=27 mm. in addition, average Nusselt number will be improved with increase of C/d in the diameter d=13 mm of the jet nozzle. but in d=27 mm, average Nusselt number will drop with increase of C/d. Revise formulae to the experience of setting up its average Nusselt number of the static system finally. while rotating the system. When Reynold number is lower, it is quite apparent in promotion of the heat transfer to rotate the effect. But as Re increases, the decline thereupon of promotion to whole heat transfer of rotatory effect. like with heat-conduction gain parameter (NuΩ/Nu0)≧1.1 as judging the datum gained in effective heat-conduction. Spray nozzle diameter d=13 mm,rotate renaud it count with lasting ratioing where renaud counting(Rer/Re) must be greater than 1.43. d=27 mm at (Rer/Re) Must be greater than 1.154. Gain the effective rotation to the heat-conduction.