Investigation of single saltwater droplet impact solidification and prediction method for macroscopic ice accretion on a flat surface

Abstract

Seawater droplet freezing threatens offshore structures, vessels and marine engine air intake systems. Yet, single droplet freezing and its link to macroscopic ice accretion are poorly understood. The paper investigates the impact of single supercooled saltwater droplets on a flat surface as its starting point. It employs the Coupled Level-Set and Volume-of-Fluid (CLSVOF) and Enthalpy-Porosity (EP) method to establish a numerical model for droplet impact freezing. The study analyzes various factors affecting single droplet spreading flow characteristics, transient heat transfer properties, and impact freezing dynamics. A mechanism equating the dimensionless impact time of a single droplet to the dimensionless impact time interval between multiple droplets is established. Moreover, a mathematical model predicting ice thickness on flat surfaces is proposed based on the freezing fraction corresponding to the Liquid Water Content (LWC) of single droplet. Finally, experimental results of ice accretion thickness on flat panel (ice blade) were obtained under different parametric conditions in an ice tunnel. Through comparative analysis, the validity of the proposed method for predicting ice accretion thickness on flat surfaces was confirmed. This predictive method effectively considers various factors such as salinity, velocity, temperature, and diameter, providing valuable insights for studying ice accretion on flat panels or the surfaces of complex structures.