The present study conducts supercooled droplet impact experiments on flat ice surfaces with varied impact velocities, initial diameters, droplet supercoolings, and ice surface temperatures. Droplet spreading at room temperature can be described by equating the inertial force to capillary and viscous forces. A universal scaling on maximum spreading can be obtained by interpolating between the laws in the capillary and viscous regimes where the dominant forces are capillary and viscous, respectively. During supercooled droplet spreading on ice surfaces, dendritic solidification occurs, forming a moving ice–water interface and leading to new droplet spreading mechanisms. The maximum spreading factor is sensitive to droplet supercooling, whereas surface temperature has a minor influence on spreading. A new dimensionless number, the icing number, is proposed to scale icing effects on a flow field, refining the law in the viscous regime for supercooled droplets. Nevertheless, icing does not affect the scaling in the capillary regime. The total influence of icing is related to the magnitude of the icing number and the competition between capillary and viscous forces. The icing number can then form a simple criterion for determining whether icing is negligible. The newly derived scaling performs well when modeling the present experimental results.

本研究在具有不同冲击速度、初始直径、液滴过冷度和冰表面温度的平坦冰面上进行过冷液滴撞击实验。液滴在室温下的扩散可以通过将惯性力等同于毛细管力和粘性力来描述。可以通过在毛细管和粘性区域中的定律之间插值来获得最大扩散的通用比例，其中主要力分别是毛细管和粘性。在过冷液滴在冰表面扩散过程中，发生树枝状凝固，形成移动的冰水界面并导致新的液滴扩散机制。最大扩散因子对液滴过冷敏感，而表面温度对扩散的影响较小。一个新的无量纲数，结冰数，提出来衡量流场上的结冰效应，完善过冷液滴的粘性状态定律。然而，结冰不会影响毛细管状态中的缩放。结冰的总影响与结冰次数的大小以及毛细管力和粘性力之间的竞争有关。然后，结冰数可以形成一个简单的标准，用于确定结冰是否可以忽略不计。在对目前的实验结果进行建模时，新导出的缩放比例表现良好。然后，结冰数可以形成一个简单的标准，用于确定结冰是否可以忽略不计。在对目前的实验结果进行建模时，新导出的缩放比例表现良好。然后，结冰数可以形成一个简单的标准，用于确定结冰是否可以忽略不计。在对目前的实验结果进行建模时，新导出的缩放比例表现良好。