不同浸润性冷表面上水滴碰撞结冰的数值模拟

对冷水滴撞击不同表面时的动力学行为和相变过程进行了模拟。通过耦合VOF和Level-set方法追踪气液自由界面，结合焓-孔隙度相变模型，模拟水滴撞击冷表面的动力学行为及相变特征。选取亲水（接触角30°）、疏水（接触角114°）和超疏水（接触角163°）3种典型浸润性的表面，计算了多种壁温条件下的水滴撞击结冰过程。结果表明提高表面疏水性，将减小水滴与冷表面的接触时间和接触面积，降低水滴内的相变速率，延缓水滴结冰的时间。在表面温度高于-15℃时，超疏水表面可以避免冷水滴的冻结黏附，保持表面洁净。将模拟得到的最大铺展直径、回缩速率以及冻结情况，与已有实验结果进行对比验证，表明了模拟方法的有效性和准确性。

Numerical simulation of droplet impinging and freezing on cold surfaces with different wettability

A strategy is presented to simulate the impact and solidification of the water droplet on different substrates. Simulations were performed using a coupled volume-of-fluid and level-set method to tracking the air-water interface and an enthalpy-porosity method to capture the phase transition. Three surface types were investigated: hydrophilic surface (contact angle 30°), hydrophobic surface (contact angle 114°) and superhydrophobic surface (contact angle 163°). The results showed that decreasing the wettability would reduce the contact time and area with the cold surface, and delay the freezing of the droplet. When temperature of the surface is higher than -15℃, the superhydrophobic surface can remain entirely ice-free under the simulated conditions. By comparing the maximum droplet spread, retraction response and time for solidification with the experimental results, the effectiveness and precision of the simulation strategy were demonstrated.