A Study on Frost Formation : The Process of Frost Formation involving the Phenomena of Water Permeation and Freezing

Abstract

The frost formation process consists of three periods : "crystal growth period", "frost layer growth period" and "frost layer full growth period". This paper studies the process in the frost layer full growth period, which is characterized by the phenomena of water permeation and freezing in the frost layer. It was shown experimentally that this process could be classified largely into two frost formation patterns, depending on the diffusion rate of water vapour. The position of the freezing interface in the frost layer was related to the water quantity held on the frost surface by surface tension and the heat flux in frost layer. Further, the frost structure in this period was composed of a freezing layer and a porous layer, and the frost properties could be estimated from this structure.