标题： 过热表面的液滴冲击 显示英文标题

标题： Drop impact on superheated surfaces

摘要： 在液体液滴撞击到高于液体沸点的光滑表面时，液滴在接触表面时立即沸腾（“接触沸腾”），或者在不接触表面的情况下形成向热表面方向的莱顿弗罗斯特蒸汽层并弹开（“温和薄膜沸腾”），或者同时形成莱顿弗罗斯特层并向上喷射微小液滴（“喷雾薄膜沸腾”）。 我们实验确定了在每个模式中可以实现的撞击行为的条件。 我们表明，在温和和喷雾薄膜沸腾模式下，撞击到加热表面上的液滴的最大无量纲扩展$\gamma$与韦伯数$\We$（$\gamma\sim\We^{2/5}$）呈现出一种普遍的标度关系——无论表面温度和液体性质如何——这比在非加热（亲水或疏水）表面上的撞击要陡得多（$\gamma\sim\We^{1/4}$）。 我们还通过干涉测量法测定了液滴下的蒸汽厚度。 显示英文摘要

摘要： At impact of a liquid droplet on a smooth surface heated above the liquid's boiling point, the droplet either immediately boils when it contacts the surfaces (``contact boiling''), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (``gentle film boiling''), or both forms the Leidenfrost layer and ejects tiny droplets upward (``spraying film boiling''). We experimentally determine conditions under which impact behaviors in each regime can be realized. We show that the dimensionless maximum spreading $\gamma$ of impacting droplets on the heated surfaces in both gentle and spraying film boiling regimes shows a universal scaling with the Weber number $\We$ ($\gamma\sim\We^{2/5}$) -- regardless of surface temperature and of liquid properties -- which is much steeper than for the impact on non-heated (hydrophilic or hydrophobic) surfaces ($\gamma\sim\We^{1/4}$). We also intereferometrically measure the vapor thickness under the droplet.