LED镁合金散热器的多尺寸翅片设计与性能分析

Design and analysis of magnesium alloy heat sink with multi-sized fins for LED application

为满足大功率LED散热结构的轻量化需求,设计了一款新型多尺寸翅片结构的LED镁合金散热器,并以散热面积相同的规则形貌散热器作为对比结构,采用Icepak热仿真软件获得两种结构的温度场及流体场,进而对比分析其散热性能.结果表明:外侧的短矮型翅片可减少对空气自然对流的阻碍作用,短高型与长矮型翅片分别能增强在翅片高度和长度上的自然对流强度,散热器沿x轴与y轴方向横切面处的空气流速分别相对提升了18%与9.4%,全局最高温度降低了2℃,表明多尺寸翅片镁合金散热器具有较明显的自然对流散热优势.最终按照设计的多尺寸翅片结构制成散热器样品,在搭建的实验测试系统中获得关键测点的温度数据,与仿真计算结果吻合较好,相对误差最大不超过8.6%,且最大输入电流条件下的最高芯片结温远低于芯片极限温度值.因此,所设计的多尺寸翅片镁合金散热器能满足LED灯具的散热需求.

In order to obtain lightweight heat sink for high-power LED application, a new magnesium alloy heat sink with multi-sized fins was designed in this paper. A regular morphology heat sink, which had same surface area as multi-sized fins heat sink, was provided as a referential sample. The heat dissipation performance of two above mentioned heat sinks were contrastively analyzed, including temperature field and fluid field, which were simu-lated using software ICEPAK. The results show that short-low fins become lighter in weight which can also reduce the impediment to natural convection from lateral fins at the same time, and short-high fins and long-low fins can extend air flow distance along its length and height. Besides, the air velocity at the cross section in the mid-dle of heat sink with multi-sized fins along the x axis and y axis are separately increased by 18% and 9.4%, and its global maximum temperature is reduced by 2℃.It is proved that the magnesium alloy heat sink with multi-sized fins in natural convection has obvious advantages in improving heat dissipation performance. Finally the test sample was fabricated in terms of the new structure heat sink, and temperature data of key measurement points were obtained by experimental test. Via calculation the results indicates that the experimental data agree well with the simulation ones, and the maximum relative error is less than 8.6%, the chip junction temperature under max supply current is much less than its limit value. Therefore, the magnesium alloy heat sink with multi-sized fins can satisfy the heat dissipation requirement.