大功率LED相变热柱加工及传热性能研究

发布时间：2018-03-28 12:11

  本文选题：大功率LED　切入点：热柱　出处：《华南理工大学》2016年硕士论文

【摘要】：随着半导体技术的飞速发展,以大功率LED为代表的电子芯片集成化、小型化和高频化程度日益提高,由此带来的空间狭小、热流密度过高等散热问题越来越凸显。本文针对LED芯片在使用中遇到的热流密度过高和普通散热器难以满足其散热需求的现状,提出一种具备高效传热性能的新型复合毛细芯热柱散热器,提出利用犁切-挤压加工方法在铜管内壁加工出三维翅结构,进一步在三维翅表面复合一层铜粉烧结芯以形成复合毛细芯;分析了烧结温度、烧结时间以及铜粉形状和粒度对复合烧结毛细芯形貌的影响机制;研究了加热功率、充液率以及毛细芯尺寸等多种关键参数对热柱传热性能的影响规律。将复合毛细芯热柱的传热性能与普通热沉以及市场同类散热产品进行了对比,测试结果表明,复合毛细芯热柱具备高效传热性能。本文主要研究内容如下:(1)提出采用犁切-挤压成形方法加工三维翅沟槽结构,重点研究了包括犁切深度ap、径向沟槽间距fr以及轴向沟槽间距fz在内的三个关键加工参数对三维翅沟槽形貌结构的影响规律。结果表明,在犁切深度为ap=0.4mm,径向沟槽间距为fr=0.4mm以及轴向沟槽间距为fz=π/25rad的组合参数下得到三维沟槽翅的形貌最优。(2)结合粉末烧结理论,分析了烧结颈的生长机制,并研究了烧结温度、烧结时间以及铜粉粒径和形状对烧结毛细芯形貌的影响规律。结果表明,当烧结温度和烧结时间分别为900℃和60min时,获得毛细芯孔隙结构形貌最好;枝状铜粉烧结毛细芯的孔隙率大于球状铜粉,并且铜粉烧结毛细芯综合性能随着铜粉粒度减小而变得更好。(3)根据LED散热需求,设计出热柱系统整体结构,主要由蒸发段、工质、冷凝段以及复合毛细芯构成。制定出热柱整体制造工艺流程,对材料选择、端盖加工、清洗、焊接以及工质灌注等每一道工序进行了分析,确保制造出满足实验要求的热柱样品。(4)搭建实验平台对热柱快速启动性能和热柱在不同加热功率、充液率以及毛细芯规格参数下的传热性能进行了测试。结果表明,热柱具备良好的热启动性能,最大传热载荷达到120W;热柱传热性能与毛细芯长度、直径以及铜粉粒径之间呈现出单向线性关系;对复合毛细芯热柱、普通热沉、单一沟槽芯热柱以及市场同类散热产品的传热性能进行了对比,结果证明复合毛细芯热柱在传热性能上具有极大优势;最后,对相同热柱样品分别在模拟热源和LED热源下的传热性能进行了比对,结果表明本文在模拟热源下获得的实验数据具备可靠性,可以为热柱应用于解决大功率LED散热提供支撑。
[Abstract]:With the rapid development of semiconductor technology, the integration, miniaturization and high frequency of electronic chips, represented by high power LED, are becoming more and more important. The problem of heat dissipation such as high heat flux is becoming more and more prominent. This paper aims at the current situation that the heat flux of LED chip is too high and the ordinary radiator can not meet its heat dissipation demand. A new type of composite capillary core heat sink with high heat transfer performance is proposed. The three-dimensional fin structure is fabricated by plough-extrusion method in the inner wall of copper pipe. The effect of sintering temperature, sintering time, shape and particle size of copper powder on the morphology of composite sintering capillary core was analyzed, and the heating power was studied. The effect of several key parameters, such as liquid filling rate and capillary core size, on heat transfer performance of hot column is studied. The heat transfer performance of composite capillary core is compared with that of common heat sink and similar heat dissipation products in the market. The composite capillary core hot column has high heat transfer performance. The main contents of this paper are as follows: 1) A plough cutting and extrusion forming method is proposed to process three dimensional fin grooves. The effects of three key machining parameters, including ploughing depth app, radial groove spacing fr and axial groove spacing fz, on the morphology and structure of three-dimensional fin grooves are studied. Under the combined parameters of ploughing depth of 0.4mm, radial groove spacing of fr=0.4mm and axial groove spacing of fz = 蟺 / 25rad, the optimum morphology of three-dimensional grooves was obtained by combining the theory of powder sintering, the growth mechanism of the sintered neck was analyzed, and the sintering temperature was studied. The effect of sintering time, particle size and shape of copper powder on the morphology of sintered capillary core was studied. The results showed that the pore structure and morphology of capillary core were the best when sintering temperature and sintering time were 900 鈩，

本文编号：1676273