Harvey Dana, Harper Joshua Méndez, Burton Justin C
Department of Physics, Emory University, Atlanta, Georgia 30322, USA.
Phys Rev Lett. 2021 Sep 3;127(10):104501. doi: 10.1103/PhysRevLett.127.104501.
During the Leidenfrost effect, a thin insulating vapor layer separates an evaporating liquid from a hot solid. Here we demonstrate that Leidenfrost vapor layers can be sustained at much lower temperatures than those required for formation. Using a high-speed electrical technique to measure the thickness of water vapor layers over smooth, metallic surfaces, we find that the explosive failure point is nearly independent of material and fluid properties, suggesting a purely hydrodynamic mechanism determines this threshold. For water vapor layers of several millimeters in size, the minimum temperature for stability is ≈140 °C, corresponding to an average vapor layer thickness of 10-20 μm.
在莱顿弗罗斯特效应期间，一层薄薄的绝缘蒸汽层将正在蒸发的液体与热固体分隔开来。在此，我们证明莱顿弗罗斯特蒸汽层能够在比形成所需温度低得多的温度下维持。通过一种高速电学技术来测量光滑金属表面上水蒸气层的厚度，我们发现爆炸失效点几乎与材料和流体特性无关，这表明一种纯粹的流体动力学机制决定了这个阈值。对于尺寸为几毫米的水蒸气层，稳定性的最低温度约为140°C，对应的平均蒸汽层厚度为10 - 20μm。
