钨铜合金电镀铜纳米线构建超疏水冷凝传热界面

Fabrication of a superhydrophobic surface by electroplating copper nanowire array on tungsten-copper alloy for enhancing condensation heat transfer

为改变钨铜合金表面的亲水特性,提升钨铜合金的冷凝传热效率,先通过多孔阳极氧化铝(AAO)模板辅助电镀的方法在钨铜表面构建铜纳米线阵列,再用十八烷基硫醇修饰得到超疏水纳米界面,从而实现钨铜合金表面冷凝状态从膜状向滴状的转变。结果表明,电镀所得的铜纳米线阵列高度均匀,进一步修饰所得的超疏水界面在大气工况下无液滴粘附。在40°C的蒸汽条件下,超疏水表面过冷度为2 K时,其热流密度为89.14 kW/cm^(2),传热系数为44.28 kW/(m^(2)·K),传热效率比光滑钨铜合金高出约1倍,并且在过冷度增大到15 K时依然保持滴状冷凝模式。

In order to improve the condensation heat transfer efficiency of tungsten-copper alloy by changing its hydrophilicity, a copper nanowire array was fabricated on the surface of tungsten-copper alloy by electroplating with porous anodic aluminum oxide(AAO) as a template, and then a superhydrophobic nanostructured surface was formed by modification with octadecanethiol. In this way, the condensation state on tungsten-copper alloy surface was transited from filmwise to dropwise. The results showed that the electroplated copper nanowire array was highly uniform, and no droplets stuck on the superhydrophobic surface obtained by further modification under atmospheric condition. In a steam of 40 °C, the superhydrophobic surface featured a heat flux density of 89.14 kW/cm^(2) and a heat transfer coefficient of 44.28 k W/(m^(2)·K) at a subcooling degree of 2 K, and its heat transfer efficiency was twice of that of the smooth tungsten-copper alloy surface. The superhydrophobic surface kept a dropwise condensation mode even when the subcooling degree was increased to 15 K.