- 學位論文
鋁材蒸氣腔體應用於LED散熱之性能研究
Thermal Performance Investigation of Aluminum Vapor Chamber Applied in LED
摘要
隨著高功率發光二極體(LED)的發展，LED的散熱問題愈趨嚴重，進而使得熱管理顯得更加重要。近年來傳統散熱模組已經無法滿足高功率LED的散熱需求。有鑑於此，本研究設計一結合熱管和熱擴散板的鋁材蒸氣腔體應用於自然對流條件，藉由工作流體於蒸氣腔體內蒸發與冷凝兩相熱傳機制，與氣態高自由度的特性，將熱量迅速且均勻擴散來達到散熱和均溫的效果。實驗中選用質輕、價格便宜且加工容易的鋁做為蒸氣腔體的外殼，內部則為微尺度溝槽式毛細結構，並以丙酮做為工作流體。本研究以實驗量測的方式進行蒸氣腔體在自然對流之下的熱傳性能表現，並以熱阻模型加以分析討論，其中針對加熱功率、工作流體充填率和蒸氣腔體長度進行比較分析。實驗結果顯示，沸騰表面過熱度達到4oC以上時，蒸氣腔體才會開始運作。當工作流體充填率50%時，有較佳的熱傳效果與溫度均勻性，且當蒸氣腔體長度大於24公分時，即無明顯的熱擴散效果。此外，蒸氣腔體熱阻分別比銅材與鋁材降低約11.3%和15.7%，使表面溫度分布均勻性增加。相較於銅材與鋁材，此種鋁材蒸氣腔體更適用於高功率LED的散熱需求。
並列摘要
With the development of high-power light emitting diodes (LEDs),heat dissipation problems become more and more serious, which raises challenges in LED thermal management. In recent years, the conventional modules can not be satisfied the need of high-power LEDs. Therefore, this study provides an aluminum vapor chamber solve the heat dissipation of high-power LEDs in natural convection condition. The vapor chamber utilizes the evaporation and condensation mechanisms to offer an excellent thermal spreading performance and more uniform temperature distribution. The vapor chamber is made of aluminum, with grooved wick structure on inner surface. Acetone is employed as the working fluid in this study. This article experimentally investigates the thermal performance of the vapor chamber applied to the high-power LEDs in natural convection. The experimental parameters include heating power, fill ratio of working fluid, and the length of vapor chamber. The results show that the vapor chamber starts to work when the superheat degree of boiling surface reaches 4oC. As a fill ratio 50%, the vapor chamber has the greatest thermal capacity and more uniform temperature distribution. The thermal performance of the vapor chamber decrease when the length of vapor chamber exceeds 24cm. Besides, compared with the copper and aluminum plate, the vapor chamber is reduced about 11.3 and 15.7% for the thermal resistance, respectively. When compared with the solid metal spreaders, the vapor chamber provides, a better choices as a heat spreader for LED cooling with high-power consumption.