Freezing Droplet Distribution Prediction for Condensation Frosting Considering Edge Effects on Structured Surfaces.

Condensation frosting is commonly observed in nature but also exerts profound effects in industrial applications. In this research, we investigate the freezing droplet distribution during condensation frosting on surfaces with variable nano/microscale structures, with particular emphasis on the interplay between surface properties and the edge effect. A theoretical model based on the physics of condensation frosting is developed to predict freezing droplet size by analyzing the influence of surface wettability, temperature, structural characteristics, and sample dimensions. This comprehensive model integrates principles of vapor diffusion for condensation, classical nucleation theory for spontaneous freezing, and analytical models for ice propagation dynamics. A distinct freezing mechanism is revealed, showing spontaneous nucleation predominantly occurring at edges, followed by propagation toward the center of the surface. The model successfully predicts the freezing droplet size distribution with a less than 17.5% deviation from the experimental results. Additionally, we explore how the surface edge affects freezing dynamics, demonstrating that edge characteristics significantly influence both spontaneous freezing delay and propagation efficiency. This study provides a pioneering approach for predicting initial frost layer characteristics on structured surfaces, which serves as a critical link between surface engineering and comprehensive frost growth modeling, and ultimately guides the development of more effective antifrost surfaces.