Particle-based model captures fine details of complete droplet freezing process

Frozen water droplets may seem unsuspecting, but they are an important consideration when engineering common structures like cables and airplanes. Because of its ubiquity, scientists constantly push to improve their understanding of droplet icing. To that end, Zhang et al. report on a particle-based model that replicates the entire icing process of supercooled droplets on cold surfaces, including recalescence.

The researchers studied the many-body dissipative particle dynamics with the energy conservation (MDPDE) method of simulating droplet icing, which employs a meshless numerical model. The method is set apart by its ability to reproduce the recalescence phase of freezing, which traditional models could not reproduce due to the recalescence’s short time scale relative to the total icing process. The model maintains the advantage of previous models to simulate mesoscopic icing, which is difficult to observe experimentally.

“Compared with the traditional computational fluid dynamics method, MDPDE has a lower computational cost and can realize the simulation of droplets’ complete icing process,” author Xiwen Zhang said.

Using this model, the scientists were able to describe the internal temperature distribution before recalescence, something rarely considered in previous studies.

They considered the initial ice mass fraction, which is necessary to account for the specific heat and density changes after recalescence, resulting in more accurate calculations for solidification time. The model lends insights on several important characteristics, such as ice shape and nucleation temperature.

“Next, there should be related research on the complete process of droplet collision icing and the icing of smaller droplets,” Zhang said.

Source: “Study on a mesoscopic model of droplets freezing considering the recalescence process,” by Chenyang Wang, Xiao Wu, Pengfei Hao, Feng He, and Xiwen Zhang, Physics of Fluids (2021). The article can be accessed at https://doi.org/10.1063/5.0064976 .