Impingement and splashing of a supercooled large droplet on a freezing water film. (December 2022)

• Record Type: Journal Article
• Authors: Yang, Zhe; Zhou, Botong; Yang, Zhigang; Yi, Xian; Du, Yanxia; Jin, Zheyan
• Is Part Of: International journal of multiphase flow. Volume 157(2022)
• Publication Date: 2022-12
• Subjects: Supercooled large droplet (SLD) -- Freezing water film -- Splashing -- Crown evolution; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2022.104263
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: A supercooled large droplet impacting on a freezing water film was studied. The evolution characteristics of the crown generated by SLD were analyzed. The dendritic ices significantly affected the formation and growth of crowns. The relationship between secondary droplets number and water film thickness was studied. Abstract: In the present study, we report for the first time the detailed dynamic processes of a supercooled large droplet (SLD) impacting on a freezing water film at different freezing moments. At the beginning of the experiment, the deionized water film was first set to a desired temperature and then triggered to freeze by further cooling. Then, a supercooled large droplet was released to impact the freezing water film at different freezing moments. Its impact and splashing processes were recorded by a high-speed camera. Besides, under room-temperature conditions, the impinging and splashing processes of a water droplet on the water film with different thicknesses were also measured. The results showed that, at the early stage of the water film freezing process, the dendritic ices could be pushed out of the water film surface due to the impact of the supercooled large droplet. Besides, the dendritic ices significantly affected the formation and growth of crowns, which could lead to the earlier crown breaks or the formation of the irregular crowns. Moreover, compared to its counterpart of the room-temperature droplet case, the evolution characteristics of the crown generated by the supercooled large droplet case were significantly different in terms of the crown top diameter, the crown base diameter, the crown height, the crown angle, and the crown lifetime. In addition, the correlations between the number of the secondary droplets and the dimensionless water film thickness were obtained and compared as for the room-temperature droplet cases and the supercooled large droplet cases.