Experimental investigation of surface wettability on frosting propagation characteristics

Abstract

The frost propagation process on surfaces plays a crucial role in the initial stages of surface condensation frosting, making it a significant aspect of the entire process. To investigate the relationship between surface wettability and the frost propagation velocity during condensation frosting, a microscopic visualization experiment platform was established. Three high-reflectivity surfaces with varying wettability were prepared to meet the experimental requirements. The frost propagation process can be divided into two stages: the freezing of intra-droplet and the ice bridge propagation between droplets. Experiment results revealed that the primary factor affecting the propagation speed of the ice bridge is the distance between the ice bridge and the droplet. As this distance reduces from approximately 16 μm to 2 μm, the propagation velocity of the ice bridge increases dramatically from around 2 μm/s to about 12 μm/s. Furthermore, the overall frost propagation velocity on surfaces with different wettability properties, were evaluated. The results indicate that the significant difference in droplet distribution characteristics and ice bridge propagation coefficients on superhydrophobic surfaces is the cause of slow frost formation during frosting on cold surfaces. This study identifies the key factor affecting the frost propagation and the inhibition of frost formation, namely, the droplet size distribution characteristics of superhydrophobic surfaces. These insights and findings provide a foundation for the design and optimization of anti-frost surfaces.