电子元件散热装置的烟囱效应分析

Analysis on the Stack Effect of Cooling Device of Electronic Components

目前中小型电子发热元件的散热以自然对流散热方式为主,针对多数散热器不能发挥其结构优势来增强自然对流,导致散热性能差、体积笨重等问题,运用计算流体力学(CFD)数值模拟的方法,设计具有"烟囱效应"结构的散热器,简化散热器模型结构,研究高、宽、热流密度的变化对自然对流的影响及三者之间的变化规律,用于指导散热器的设计。结果表明:热流密度为1 000W/m2、高为50mm时,温度达到最低值时的宽度为19mm,此时为该热流密度下的临界点;以临界点时的高宽比为基准,高宽比小于基准时,有回流现象;热流密度从1 000W/m2增加到15 000W/m2,不同高度下临界宽度先减小,后趋于固定值。

Currently the natural convection cooling is the main cooling way of the small and medium sized electronic heating elements,considering most of the radiator can not play the advantage of its structure to enhance natural convection,leading to poor heat dissipation,bulky and so on,using computational fluid dynamics（CFD）numerical simulation methods to design of ＂tack effect＂ structure of the radiator,simplify the structure of the radiator,study the effect of the changes of height,width and heat flux on natural convection,and the variation among the three factors,and use it to guide radiators.The results show that： when heat flux is 1 000W/m2 and height is 50mm,19mm is the critical width as the temperature reaches the minimum value,this time of the value is the critical point;considered the high aspect ratio of critical point as the reference value,when the aspect ratio less than the reference value,there is the reflow phenomenon occurred;As heat flux increased from 1 000W/m2 to 15 000W/m2,the critical width first decreases,then tends to a fixed value in different height.