多孔金属布置对热沉传热特性影响的数值研究

Numerical Study on Thermal Characteristics of Heat Sinks With Different Porous Metallic Foam Configuration Designs

本文基于传统微通道热沉的物理模型,建立了完全填充、三角形填充、梯形填充、渐扩梯形填充及底层填充5种不同几何布置形态的多孔金属微通道热沉的数值模型。在层流流动的范围内,对不同布置形态多孔金属微通道热沉的阻力系数、平均Nu数、热阻、有效温控系数及能效因子等相关参数进行了数值研究,并应用场协同原理对多孔金属强化微通道的换热性能进行了分析。结果表明：微通道热沉中填充多孔金属后可显著改善速度场与温度场之间的协同性,填充不同多孔金属布置形态的微通道热沉可使平均协同角减小9.6°~23.2°左右;5种不同多孔金属布置形态的热沉中,完全填充热沉的热阻最小,冷却效果最好;等泵功情况下,当Re数大于150时,完全填充和梯形填充热沉的综合换热性能均优于传统微通道。

In this paper,five types of heat sinks with different porous metallic foam configuration designs（fully-filled,triangle-filled,trapezoid-filled,outlet enlarged trapezoid-filled and bottom-filled）are established based on the traditional mini-channel heat sink.The flow and thermal characteristics,including friction factor,averaged Nusselt number,thermal resistance,thermal control effectiveness and thermal performance ratio were investigated in laminar flow range.Moreover,the heat transfer enhancement principle of metallic foam heat sink was analyzed by employing field synergy principle.The results show that the metallic foam filled heat sink can improve the field synergy between the velocity and temperature gradient and the averaged field synergy degree can decrease about 9.6 to 23.2°.The fully-filled heat sink has the minimum thermal resistance in all the configuration designs and holds the best cooling performance.Under the same pumping power,the thermal performance of the fully-filled and the trapezoid-filled heat sink are better than the non-porous filled heat sink when Re larger than 150.