Chapter 8 – Research on mechanism and measurement technology of frost formation of micro water frosting

Micro water frosting is widely found in industrial applications involving different temperature, pressure, and gas composition conditions such as cryogenic wind tunnels, in-orbit spacecraft, microchannel heat exchangers, and cryopumps. In most cases, frost formation can cause significant damage to the corresponding industrial processes, so it is necessary to measure the properties of the frost layer, reveal the mechanism of the frost formation process, and design frost suppression and defrost strategies. Compared with frost formation in general cold and wet air conditions, the study of frost formation with micro water is more difficult. The frost layer produced by micro water is difficult to measure. This chapter introduces the current research on frost formation of micro water from two aspects: frost formation mechanism and measurement methods. In terms of frost formation mechanism, the nucleation mechanism of micro water, the growth characteristics of frost layer and the deposition, and the sublimation characteristics of micro water are analyzed. In terms of frost formation measurement methods, the principles, application scenarios, and advantages and disadvantages of visual measurement technology, optical measurement method, and low-temperature micromass measurement technology are described in detail.