蜂巢式散热鳍片应用于高功率LED散热的研究

近年来由于节能减排的议题,低耗能的LED光源受到极高重视,其中高功率LED本身最大的难题在于散热,过高的温度会降低LED的发光效率、寿命,甚至使颜色改变.然而不论是传统的散热技术,或是较新型的散热技术,在设计LED灯具上,皆难以降低成本使其普及大众,因此发展新的散热技术一直是重要的议题.本研究将利用蜂巢结构与自然对流散热的优点,结合烟囱效应,开发出特殊的散热方式,即蜂巢式散热鳍片.研究分析的方式主要利用CFD-RC软件包进行模拟,并配合实验做验证.研究发现,对散热效能影响最大的是高度,理想的高度选择约在6～10 mm,可以解的瓦数为13～14 W,而重量为75～125 g,再配合本研究特殊设计,重量还可以再减轻1/3,且几乎不影响散热效能.

Study of an LED Device with a Honeycomb Heat Sink

Previous studies show that the lighting quality of LED largely depends on operating temperature. LED without thermal management may fail early due to thermal runaway, epoxy degradation, and thermal stress under high-operating temperatures. In this study, the performance of a honeycomb heat sink was investigated by experimentation and three-dimensional numerical models. Two kinds of honeycomb models were proposed to demonstrate the performance of a heat sink with single and multiple heat sources for LED thermal management. The performances of innovative honeycomb heat sinks depend on the number of cells, aspect ratio, and the rib-space ratio. The simulated results indicated that the performance varies a little when the conductivity is over 50 W/(m·K-1). Compared to the simulated heat flux ratio 0. 95, the measured heat flux ratio 0. 93 at θ=30° was slightly lower. The measured performance of the lump and stack (5 pieces) honeycomb heat sink can respectively keep 13. 761 W and 13. 338W under the dummy heater at 67℃ and the ambient temperature at 27℃. The innovative design with nine pieces of layers that are drilled to reduce their weight can effectively dissipate the heat by natural convection in the application of a high-power LED street lamp.