渐变孔隙率对泡沫铝矩形通道热沉流动和换热性能的影响

Numerical investigation in the effects of gradient porosity material on flow and heat transfer performances of foam metal heat sinks

风冷是最普遍的电子器件散热方式。对填充渐变孔隙率泡沫铝的热沉的流动与换热性能进行CFD模拟,考察了孔隙率分别沿流动方向和高度方向发生梯度变化对热沉性能的影响。结果表明:与均匀孔隙率热沉相比,孔隙率沿高度方向渐变的热沉压力损失减小,最佳的孔隙率渐变方式为沿高度方向由0.963 0递减至0.700 0,与当量孔隙率0.831 5的均匀孔隙率热沉相比,明显提高了泡沫铝热沉的综合性能。当进口速度高于3.0 m/s后,渐变孔隙率热沉的综合性能甚至优于高孔隙率(0.963 0)的均匀孔隙率热沉。

Air cooling is the most common cooling technique for electronic devices. However, less attention has been paid to the flow and heat transfer performances in rectangular passage of heat sinks inserted with gradient porosity metal foam. Thermo-hydraulic and heat transfer performances of heat sinks with gradient porous material (GPM) were investigated numerically. The effects of porosity graded change in flow direction and in height direction (z direction) on the overall heat transfer coefficient were examined. The results show that heat sinks with porosity change in z direction has a lower pressure drop. Moreover, the configuration with a porosity decreasing from 0. 963 0 to 0. 700 0 in the z direction can achieve a larger PEC (performance evaluation criterion) than HPM (homogeneous porosity material) heat sinks with a porosity of 0.831 5. The performance with GPM is even superior to the HPM heat sink with a porosity of 0. 963 0 at larger inlet air velocities than 3. 0 m/s.