Estimating case temperature of a component in platefin_heat sink_for natural convection heat transfer in an enclosure.pdf
heatsink thermal resistance prediction
我自己写了一篇如何估算自然对流条件下,heatsink的热阻的文章。自己写的,花了很长时间,所以买的贵一点,大家不要拍砖啊,哈哈。根据文章的公司,自己可以制作出一个spreadsheet,输入heatsink的各种参数,很方便也很容易计算出heatsink的热阻的。热阻计算包括了heatsin的导热热阻,扩散热阻,对流热阻以及热辐射带来的影响。我已经做和数个heatsink的实际测试,并和计算值做了比较,发现还是蛮准确的,误差可以控制在5%以内。希望对大家以后的工作有帮助,,,
Estimating case temperature of a component in a plate‐fin heat sink for natural convection heat transfer in an enclosure
1.introduction
Natural convection heat transfer is most often used in many electronic devices as the way of thermal management solution due toits high reliability and low‐cost. But compared with forced convection, the air motion of natural convection is much weaker, which will amount to low heat transfer coefficient, and so heat sink is usually used in natural convection application to expand surface areas for heat dissipation. This article explains how to predict the case temperature of key components encapsulated in enclosure under natural convectionapplication when plate‐fin array heat sink is used.
Most fluids, including air, expand when their temperature rise. This expansion itself reduces the density of local fluid and increases its buoyancy, which will force the fluid to go up. When a powered component transfers heat to its adjacent air, it causes a similar air movement. The movement of heated air induces the cooler air towards the hot component and the cool air is heated by the component and ries once again and this process repeats which makes the hot component reach a thermal tradeoff. Figure 1 shows the effect of natural convection in plate‐fin heat sink. We can see the heated air rises among the internal fins while cool air is drawn into the base of heat sink from its sides. Because natural convection is closely related to the force of gravity, the orientation of heat sink is very important. And this article will focus on the discussion of being oriented horizontally heat sink.
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