直肋散热器结构对其散热特性影响的数值研究

Numerical Investigation of Effects of Straight Rib Radiator Structure on Heat Dissipation Characteristics

利用Flo THERM热仿真软件,研究了直肋散热器基板与肋片高度耦合变化对其散热特性的影响,同时还设计了风扇与肋片组合形式的散热器,并与直肋散热器散热特性进行比较。研究表明:1)散热器表面的平均换热系数随空气流速的提高而逐渐升高,但其升高幅度随风速的提高而逐渐降低;2)基板和肋片总高度一定时,当基板与肋片高度比大于10%时,芯片节点温度随肋片高度的增加而降低,而高度比小于10%时,增加肋片高度,芯片节点温度几乎保持不变,散热器整体温度分布不均匀性却增大;3)相同空气流速下,风扇与肋片组合形式的散热器所对应的芯片节点温度要低于直肋散热器,但随着空气流速的提高,风扇对芯片节点温度的影响逐渐减小。

The influences of the height variation of substrate and fin on heat dissipation characteristics are investigated by Flo THERM thermal simulation software. Simultaneously, the radiator which consists of fan and fin is designed, and its heat dissipation characteristics are compared with the straight rib radiator. It discovers that： 1） The average heat transfer coefficient gradually increases with the air velocity, but the rate is reduced. 2） When the total height of substrate and fin is constant, the chip node temperature decreases with the fin height in the case of the substrate to fin height ratio greater than 10%, while in the case of the ratio less than 10%, the chip node temperature is almost unchanged, but the radiator temperature distribution becomes uneven. 3） For the same air flow rate, the chip node of the radiator which consists of fan and fin is lower than that of straight rib radiator, but the extent of variation is reduced by the increasing air flow rate.