摘要
高功率微波装置在运行时面临的高热流密度散热是当前热控必须解决的难题。微小通道热沉散热结构简单,换热能力突出,在一定程度上能够解决高热流密度散热的问题。但使用微小通道热沉散热时,散热面温度在沿工质流动方向不断升高,这对器件稳定运行不利。而射流冲击技术中流体垂直于热源喷射,温度边界层薄,温度梯度大,换热效果强。将射流冲击技术与微通道热沉相结合,不仅能提高换热系数,增大换热量,而且能实现良好的温度均匀性。对高热流密度下射流冲击微小通道热沉进行数值模拟,分析不同射流孔径对其传热和流动特性的影响。结果表明,增大远离出口处的射流孔径,有利于提高传热效率和减小流动阻力。优化后的射流微通道热沉,在质量流量为14 g/s时,换热系数接近39 000 W/(m^2·K)。
How to dissipate heat effectively is the important topic for high power microwave devices.The conventional straight micro-channel heat sink which has been considered as an effective heat removal tool has the attributes of simple structure,large convective heat transfer coefficient and high surface area to volume ratio.But the increase of temperature of the dissipating surface along the direction of the fluid flow will influence the stability of electronic components.For jet impingements,the way to obtain a quite uniform temperature distribution is the use of matrix of jets,which has thinner temperature boundary,higher temperature gradient and larger heat exchange coefficient by fluid perpendicular impinging cooled object.The micro-channel heat sink combined with jet impingement not only has large heat exchange coefficient but also improves the temperature uniformity of the cooled object.In this paper,performance of micro-channel heat sink combined with jet impingement for high heat flux density cooling is simulated with numerical method.The effects of different jet apertures on the heat transfer and flow characteristics are analyzed.The results show that increasing the pore size away from the exit is beneficial to increase the heat transfer efficiency and reduce the flow resistance.The optimized heat transfer coefficient of the micro-channel heat sink combined with jet impingement is closed to 39 000 W/(m^2·K),when the mass flow rate is 14 g/s.
作者
潘瑶
刘欣
PAN Yao;LIU Xin(China Academy of Launch Vehicle Technology,Beijing 100076,China)
出处
《太赫兹科学与电子信息学报》
北大核心
2019年第4期661-665,共5页
Journal of Terahertz Science and Electronic Information Technology
关键词
高功率微波技术
微通道热沉
射流冲击
数值计算
传热特性
high power microwave technology
micro-channel heat sink
jet impingement
numerical simulation
heat transfer characteristics
