A numerical and experimental study of wavy ice-structure in an asymmetrically cooled parallel-plate channel

Abstract

Ice formation of flowing water in a pipe or a channel, whose wall is kept at a uniform temperature below the freezing temperature of the water, is a basic engineering problem. It Introduces many practical problems, such as pressure drop, diminution of flow rate and sometime, breakage of the pipe as a result of flow blockage by ice. The phenomenon of freezing of flowing water involves interactions between the turbulent flow, the shape of the ice layer and the heat transfer at the ice-water interface. Under certain conditions these interactions result in an instabilily of the ice layer. This instability is caused by the strong laminarization of the turbulent flow due to converging ice layers in the entrance region of the cooled channel and results in a wavy ice structure. Wavy ice layers with one wave, occuring in a parallel.plate channel subjected to symmetrically oooled walls were investigated experimentally by Seld et al. and by Weigand and Beer. More recently Weigand and Beer were able to predict numerically the shape of wavy ice layers with one wave occuring in a symmetrically cooled channel. Wavy ice layers in a parallel-plate channel with one wave in the case of asymmetrically cooled walls were investigated experimentally by Tago et al. and by Weigand and Beer. No numerical calculation of asymmetric wavy freezing fronts was done in the past. Therefore, the subject of this paper is the presentation of a numerical model for calculating steady state ice layers with one wave in the entrance region of an asymmetric cooled channel. The method is based on a work performed by Weigand and Beer. The given numerical study is supported by a detailed experimental investigation.