衝擊噴流冷卻於圓柱型散熱鰭片之熱流場模擬分析

電子元件過熱問題一直是設計工程師所須面臨之挑戰。隨著半導體製程輕薄短小設計概念的影響，電子元件體積日趨微小化。同時伴隨著實際功率需求的增加，其所使用電子元件之單位面積發熱量亦大幅增加。因此，如何提升電子元件散熱效能，成為一個重要的課題。由於衝擊噴流具有局部冷卻、快速散熱等優點，搭配具有高熱傳導性、散熱面積大的散熱鰭片，產生電子元件快速排除熱量效果，則為研究者所積極投入研究之主題。本研究利用計算流體力學軟體FLUENT為工具進行數值模擬，在不同的噴嘴入口流速、噴嘴至散熱鰭片頂端距離、噴嘴直徑大小、及噴嘴間距條件下，探討單、雙噴嘴型態之空氣衝擊噴流冷卻作用於圓柱型散熱鰭片之熱流現象。研究結果顯示，增加噴嘴入口流速會降低熱阻值，但在高流速時下降幅度會減緩。噴嘴至散熱鰭片頂端距離太近與太遠均會影響到熱傳效益，經數值模擬之後，得知較適當的距離為36~63mm。較大的噴嘴直徑衝擊在散熱鰭片表面的冷卻流體會較多，所以熱阻值較低。噴嘴間距在低雷諾數時，12mm為最佳距離，高雷諾數時並結合大直徑的噴嘴可將最佳間距拉長至14mm。整體而言，綜合二種噴嘴型態於各項參數條件下做比較，雙噴嘴具有較優異的散熱效能。

關鍵字

衝擊噴流；計算流體力學；噴嘴；散熱鰭片

並列摘要

The overheating problem of electronic components has been the serious challenge for designers to face. With the minimizing design concept of semiconductor component manufacture, the size of electronic components reduces gradually. At the same time, with the electronic component demanded power rising, the heat generation of per unit area also increases significantly. Therefore, how to improve the heat removal performance of electronic components has become an important research issue. Because impingement jet combining with heat sinks has local cooling, rapid heat removal advantages, it can rapidly remove heat from electronic components. There are more and more researchers devoting their efforts to this topic. In this study, numerical investigation of thermal and fluid flow phenomena of a cylindrical pin-fin heat sink under different nozzle inlet velocities, distances from the nozzle to the top of the heat sink, nozzle diameter, space between nozzles, for single or double nozzle type air impinging-jet cooling has been conducted by using FLUENT computational fluid dynamics software. The results showed that increasing the nozzle inlet velocity will reduce the thermal resistance, but the decline decreases gradually at high flow rate. Distance from the nozzle to the top of the heat sink too close and too far will affect the heat transfer efficiency. According to the numerical simulations, an appropriate distance is the distance between 36~63mm. The larger diameter of the nozzle will induce more cooling flow to heat sink surface and lower thermal resistance. Nozzle spacing at low Reynolds number, 12mm is the best distance. At high Reynolds number and the large diameter of the nozzle condition, a better spacing can be stretched to 14mm. Summarily, a double-nozzle impingement-jet flow has better thermal performance.

並列關鍵字

Impingement-jet ； Computational fluid dynamics ； Nozzle jet ； Heat sink

參考文獻

[7] 劉興和，「柱型散熱鰭片幾何尺寸影響熱傳性能之研究」，中原大學，碩士論文，民國94年。

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[3] Masud Behnia, David Copeland, Denpong Soodphakdee, “A Comparison of Heat Sink Geometries for Laminar Forced Convection：Numerical Simulation of Periodically Developed Flow,” the sixth Intersociety Conference on Thermal Phenomena in Electronic systems, pp.310-315, May 1998.

[4] Maveety J. G., and Jung H. H., “Design of an Optimal Pin-Fin Heat Sink with Air Impingement Cooling,” International Communication on Heat and Mass Transfer, Vol. 27, pp. 229-240, February 2000.

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衝擊噴流冷卻於圓柱型散熱鰭片之熱流場模擬分析

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