功率模块正弦微通道热沉周向传热特性分析

Circumferential Heat Transfer Analysis of Sinusoidal Microchannel Heat Sink on Power Module

针对飞行器大功率电动伺服系统中功率模块散热能力不足的问题,设计了正弦波式微通道热沉,以去离子水为冷却工质对功率模块进行水冷散热。建立该热沉数值模型后,对正弦微通道的周向非均匀传热特性和工作性能开展研究,并探讨了发热功率、进口雷诺数及正弦通道几何参数对热沉传热性能的影响。结果表明,通道壁温及局部热流沿圆周呈非均匀分布,最高温度和热流出现在靠近加热基底的下部中心观测线区域,壁温和热流均随正弦通道几何构型呈现显著的周期性波动,且截面圆周各位置的局部传热系数也出现剧烈波动,周向截面中最大传热系数出现在通道上下中心点位置。低热流下热沉表现出较好均温性,不同热流时Nu和泵功基本一致。随着进口雷诺数增大,热沉均温性、热阻及Nu均得到改善,但所需泵功显著增长。此外,正弦通道幅值和波长均对热沉综合性能产生显著影响。

Aiming at the heat dissipation requirement of high-power electrical servo system on flight vehicles, the heat sink with sinusoidal microchannel of power module is designed in this paper, and the deionized water is implemented as the coolant. After establishing the numerical model of heat sink, the investigation of circumferential non-uniform heat transfer characteristic and thermal performance in sinusoidal microchannel heat sink is carried out. The influence factors such as heating power, inlet Reynolds number and geometric parameters on thermal performance of the sinusoidal microchannel heat sink are explored. The simulation results indicate that the non-uniform circumferential distribution of inner wall temperature and local heat flux is exhibited, the maximum temperature and local heat flux appear at the bottom observation line of the center region close to the heating substrate. The inner wall temperature and heat flux fluctuate periodically following with the geometric structure of sinusoidal microchannel, and remarkable oscillation of the local heat transfer coefficient occurs simultaneously, meanwhile the maximum value locates at the center point of wavy channel. The lower heating power corresponds with the better temperature uniformity, and the Nu and the required pumping power are constant at various heat flux. With the enlargement of inlet velocity, the evaluation parameters, namely temperature uniformity of heat sink, thermal resistance and Nusselt number are all improved. In addition, both the amplitude and wavelength of sinusoidal channel play an important role on the overall thermal performance of heat sink.