论文标题
在纳米级润湿受控的沸腾
Wetting controlled boiling at the nanoscale
论文作者
论文摘要
沸腾是当液体在其汽化温度上加热时发生的过平衡过渡。在纳米级，沸腾可能是由浸入水或纳米复合材料表面的辐照的纳米颗粒触发的，并且通常会导致微探索。通常认为，当局部流体温度超过其旋转温度，水约573 K时，纳米级沸腾是同质发生的。在这里，我们采用分子动力学模拟来表明纳米级沸腾是一种异质现象，当水温超过润湿依赖性的开始温度时。如果固体表面是弱润湿的水，则该温度可以低于旋转温度。此外，我们表明沸腾是一个由固定液体界面热电导控制的缓慢过程，事实证明，在相变发生后，该过程大大减少了成核的时间。我们通过考虑浸入水中的球形金属纳米粒子和具有纳米级润湿异质性的固体表面来说明这一结论的普遍性。这些结果铺平了使用纳米级图案表面来控制沸腾的方法。
Boiling is the out-of-equilibrium transition which occurs when a liquid is heated above its vaporization temperature. At the nanoscale, boiling may be triggered by irradiated nanoparticles immersed in water or nanocomposite surfaces and often results in micro-explosions. It is generally believed that nanoscale boiling occurs homogeneously when the local fluid temperature exceeds its spinodal temperature, around 573 K for water. Here, we employ molecular dynamics simulations to show that nanoscale boiling is an heterogenous phenomenon occuring when water temperature exceeds a wetting dependent onset temperature. This temperature can be 100 K below spinodal temperature if the solid surface is weakly wetting water. In addition, we show that boiling is a slow process controlled by the solid-liquid interfacial thermal conductance, which turns out to decrease significantly prior to phase change yielding long nucleation times. We illustrate the generality of this conclusion by considering both a spherical metallic nanoparticle immersed in water and a solid surface with nanoscale wetting heterogeneities. These results pave the way to control boiling using nanoscale patterned surfaces.
