超亲水微纳复合结构表面热沉强化润湿与传热实验

利用碱辅助的表面氧化法在紫铜微槽群热沉表面生成了氢氧化铜纳米棒阵列结构，制备出一种全新的超亲水微纳复合结构表面热沉。并以蒸馏水为液体工质，进行了纯蒸发条件下微槽群热沉、微纳复合结构表面热沉和超亲水微纳复合结构表面热沉的润湿及传热特性的对比实验研究。实验结果表明：氢氧化铜纳米棒阵列结构使得原始亲水表面的亲水性更好，随着表面纳米棒数量的不断增多，接触角不断减小，最低为9.5°，可以进一步形成超亲水微纳复合结构表面。与无纳米结构的微槽群热沉相比，在相同输入加热功率下，微纳复合槽群热沉具有更高的液体润湿高度和更好的传热性能，而超亲水微纳复合结构表面热沉的形成会进一步提高强化润湿和传热效果，相比于紫铜微槽群热沉，超亲水微纳复合结构表面热沉内液体的润湿高度提高了300%，表面温度降低了15℃左右。

Wetting and heat transfer enhancement of superhydrophilic micro-nano hybrid surface heat sinks

Cu(OH)₂ nanorods array was synthesized on the surface of copper microgrooves heat sink by alkali assistant surface oxidation technique in this study, to generate a novel superhydrophilic micro-nano hybrid surface heat sink. Then, the wetting and heat transfer characteristics of copper microgrooves, micro-nano hybrid surface and superhydrophilic micro-nano hybrid surface heat sinks were compared at evaporation conditions, where distilled water was served as working fluid. The experimental results showed that Cu(OH)₂ nanorods array made the original hydrophilic surface more hydrophilic, the contact angle of water decreased with the amount of nanorods on the surface increases. The minimum contact angle can reach 9.5°, which results in the formation of the superhydrophilic micro-nano hybrid surface heat sink. Compared with the microgrooves heat sink without nanostructure, at the same input power, the micro-nano hybrid surface heat sink has better wetting and heat transfer characteristics. Additionally, the superhydrophilic micro-nano hybrid surface heat sink exhibits a more superior enhanced wetting and heat transfer characteristics. Compared with the copper microgrooves heat sink, the liquid wetting length increasement can reach 300% in the superhydrophilic micro-nano hybrid surface heat sink and the surface temperature is reduced approximately 15℃.