为了研究采用微槽群复合相变换热技术的大功率太阳花散热器多角度投光的方向效应及综合散热性能, 实验研究了散热器高度、功率以及采用微槽群复合相变换热技术后的过余温度、平均对流换热系数随出光倾角的变化规律, 并获得了出光倾角的Ra与Nu关联式。研究结果表明: 出光倾角小于90°时, 微槽群散热器热源过余温度大幅低于型材散热器, 在高度为90 mm, 出光倾角为30°, 输入功率为80,100,120,200 W时热源温度分别降低了11.6,13.3,18.9,26.7 K, 呈现出功率越大降幅越大的趋势; 出光倾角大于90°时, 微槽群散热器热源过余温度略高于型材散热器, 原因是微槽群散热器内部的真空环境影响散热器的均温性; 输入功率越高, 方向效应越明显; 散热器高度越低, 平均对流换热系数越大, 对比高度60 mm与高度90 mm, 在出光倾角为0°时, 功率为80,100,120 W时分别提高了27.5%、23.8%和24.2%。因此, 设计LED灯具散热器时应综合考虑散热器的方向效应。

In order to study the orientation effects and the comprehensive heat dissipation performance of the high power radiator heat sink with the phase-change heat transfer in capillary microgrooves heat sinks, the experiment studies the variation of height, power and whether using the phase-change heat transfer in capillary microgrooves heat sinks on excess temperature and the mean convection heat transfer coefficient with the installation angles. And the correlations between the Ra and Nu are obtained. The results show that when the installation angle is less than 90 degrees, the excess temperature of heat source for microgrooves heat sinks is much lower than that of the section heat sink. When the installation angle is 30 degrees, the height is 90 mm, the input power is 80, 100, 120, 200 W, the heat source excess temperature 11.6, 13.3, 18.9, 26.7 K are reduced respectively, and the greater the input power, the greater the reduction. When the installation angle is greater than 90 degrees, the excess temperature of the microgrooves heat sinks is slightly higher than that of the section heat sink, and the reason is that the vacuum environment inside the microgrooves heat sinks affects the temperature uniformity, the higher the input power, the more obvious the orientation effects. The lower the height is, the greater the mean convection heat transfer coefficient is. When the installation angle is 0°, the input power is 80, 100, 120 W, compared with height 60 mm and height 90 mm, the mean convection heat transfer coefficient increased by 27.5%, 23.8% and 24.2%. Therefore, the orientation effects of the radiator should be considered when designing the radiator for LED lamps.