On the experimental and theoretical model for ice crystal characteristics near a substrate. (May 2020)

• Record Type: Journal Article
• Authors: Chen, Gong; Kong, Weiliang; Wang, Liping; Wang, Fuxin
• Is Part Of: International journal of heat and mass transfer. Volume 152(2020)
• Publication Date: 2020-05
• Subjects: Substrate-icing -- Ice crystal structure -- Thermal diffusion -- Local supercooling; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2020.119462
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlight: Phenomenon of morphology variation within single ice crystal is observed from the experiment, which is hardly found in free-icing cases. Extend and characteristics of morphology variation are largely depends on initial supercooling degree of supercooled water field. Crystal branching structure parameters, branching ratio, branching angle and branch width, are measured as the variable for crystal structure diversity. modeling of thermal condition along with crystal growing is described by extending "semi-infinite body heat transfer". With such newly established model, local supercooling degree evolution could be generally estimated with known initial thermal condition. Abstract: For better understanding the mechanism of ice cohesion on a solid substrate, an experimental study on ice crystal structure growing from a substrate is conducted. The characteristics of crystal structure as well as their growing patterns in different supercooling degrees are observed and recorded. Besides, theoretical analysis has been carried out to identify the heat diffusion effect on crystal growing. Different from the uniform morphology and constant growing velocity observed in previous researches, it is found that the side branches upon bottom part of the crystal are usually wider and more disorderly configured while those upon upper part are always more slender and more regularly distributed. In addition, crystal growing velocity changes continuously in vertical direction with a trend of convergence. Higher supercooling degree enhances such structure evolution and advances convergence of the growing velocity. Crystal structure diversity is determined by the principle of local transient temperature evolution due to the thermal diffusion from substrate. A model is presented to estimate local supercooling degree at different height from substrate and its regularity of evolution. Comparisons are made between our results and relevant literatures for correlation.