Melting Characteristics of Frozen Sessile Water Droplets under Shear Airflow

Melting of frozen droplets on a solid surface under shear airflow is widespread in nature and industrial fields. However, research on its underlying mechanisms remains limited compared to natural convection. In this study, melting experiments are conducted on frozen water droplets on a solid surface under shear airflow to systematically investigate the effects of airflow, surface, and droplet parameters on melting characteristics. The results show that the ice-water interface propagates upward during the melting process, with the ice layer floating on the droplet top due to the density difference between ice and water. The melting process under natural convection is driven by Marangoni flow, enhancing the heat exchange between the droplet and the surface. Shear airflow not only intensifies the convective heat transfer between the droplet and the ambient air but also enhances the internal flow within the droplet, further improving the heat exchange with the surface. When the airflow temperature exceeds 0 °C, these two effects work synergistically to accelerate melting; otherwise, they exhibit a competitive relationship. Furthermore, the melting time is shortened by increasing the airflow velocity, elevating the airflow and surface temperatures, or reducing the droplet volume. Furthermore, a heat transfer model for the melting process is established, quantitatively revealing the influence of convective heat transfer and internal flow. A predictive correlation for the melting time is derived by introducing an equivalent thermal conductivity to modify the liquid phase conductivity and coupling it with external convective heat transfer, yielding a relative deviation of less than 20% compared to experimental data. This work provides guidance for the optimized design of deicing systems in shear airflow environments.