Droplet impact and icing behaviors on flat surfaces

The phenomenon of impact and icing of water droplets is widely present in many engineering practical fields. Understanding the mechanism of impact and icing of water droplets is of great significance for improving prediction accuracy. Droplet impact and icing behaviors on flat surfaces are investigated. First, the spreading and height factors of impact droplets at room temperature are obtained from experiments with the influence of Weber number and contact angle studied. As the Weber number rises and the contact angle falls, spreading velocity accelerates, enhancing spreading and maximum spreading factors. Additionally, the Weber number increase speeds up the height reduction of the droplet, lowering the temporal height factor and first local minimum height factor. The minimum height factor does not change with the surface characteristics. Then, based on the inherent morphology of water droplets at the onset of impact, we establish a theoretical model for the maximum spreading factor of ellipsoidal water droplets under various initial aspect ratios, and the deviations of all calculated data are within the range of −5% to 25%. Furthermore, the impact and icing processes of water droplets on cold surfaces are observed. The impact droplet exhibits a larger stable spreading factor and cannot fully rebound on superhydrophobic surfaces. This chapter enhances our comprehension of the interplay dynamics between water droplets and surfaces during impact and icing, offering valuable insights for applications and technologies relevant to icing/frosting.