散热器翅片间距的选取及其与微型风扇的匹配

Determination of the Fin Gap of Heat Sink and its Match with Miniature Fan

由风洞试验,测试得到一笔记本电脑系统的阻抗特性曲线及其微型风扇的性能曲线,同时对散热器翅片间流道内的空气流动与传热特性进行了分析与计算.计算结果表明,流动及换热的入口段长度占整个流道长度的比例较高,流动与换热入口段的影响明显.空气流量增加,可使散热量增加,但空气流量增加到一定量后,散热量的增加越来越不明显.在散热量一定的条件下,减小散热器翅片间距,可减小空气流量.根据系统阻抗特性曲线及微型风扇性能曲线,空气流量的减小可降低整个系统的压降,从而减小微型风扇的功耗,降低其噪音。

With the wind tunnel tests,the system impedance curve and the miniature fan characteristics curve of a laptop have been obtained.Meanwhile,the pressure drop of air flow through the heat sink and the total heat transfer rate from the heat sink to the air has been calculated and results have been analyzed.It shows that the hydrodynamic entrance length and thermal entrance length take up a high percentage of the total flow channel length,and the effects of entrance of both flow and heat transfer are evident.With the increase of air flow rate,the amount of heat dissipation increases,but after certain air flow rate,the increase of heat dissipation is not evident.However,minimizing the fin gap can reduce the air flow rate while dissipating same amount of heat.Based on the system impedance curve and the miniature fan characteristics curve,the reduction of air flow rate can lower the pressure drop of the whole system,resulting in low power consumption and low noise of the miniature fan,which is beneficial to the operation of the laptop.