Experiments on Natural Convective Air Cooling of a PCBs Array in a Closed Casing with Inclination
Experiments on Natural Convective Air Cooling of a PCBs Array in a Closed Casing with Inclination
复制标题
倾斜封闭箱体内PCB阵列自然对流空气冷却实验
DOI：
10.1007/978-94-011-1090-7_8
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Z. G. Wang
中科院分区：
文献类型：
--
作者：
F. Mayinger;Z. G. Wang
本文介绍了在倾斜的封闭外壳中印刷电路板（PCB）阵列自然对流空气冷却的实验研究。结果表明，在两种情况下（无倾斜和有倾斜），套管顶壁上都存在不稳定的热边界层。这种不稳定的边界层与从 PCB 之间的通道上升的气流相互作用，产生涡流和温度振荡。在倾斜的外壳中，热空气聚集在外壳的上角，冷空气落到下角。因此，对靠近壳体下角的区域的PCB的冷却效果增强，而对靠近上角的区域的PCB的冷却效果减弱。需要注意的是，位于上角附近的 PCB 的温度可能会超过为水平调整外壳设计的允许最高工作温度，并导致电子元件过热。从实验结果推导出的经验相关性以 N u= f (Ra, a) 的形式呈现，修正通道瑞利数范围为 102 至 105，倾斜角为 0 至 30。
This paper presents an experimental study of natural convective air cooling of a printed-circuit-boards (PCBs) array in a closed casing with inclination. The results reveal that in both cases (without and with inclination) an unstable thermal boundary layer exists on the top wall of the casing. This unstable boundary layer, which interacts with the air flow rising up from the channels between the PCBs, produces vortex flow and temperature oscillation. In the inclined casing warm air gathers together in the upper corner of the casing and cold air falls down to the bottom corner. Therefore, the cooling effect on the PCBs in the region near the bottom corner of the casing increases and that in the region near the upper corner decreases. It should be noted that the temperature of the PCBs located near the upper corner can exceed the allowed maximum working temperature designed for levelly adjusted casing and cause an overheating of electronic elements. An empirical correlation deduced from the experimental results is presented in the form of N u= f (Ra, a) with the modified channel Rayleigh number ranging from 102 to 105 and with an angle of inclination from 0 to 30.