Author(s): Ivar Horjen
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Keywords: No Keywords
Abstract: A numerical model of trash rack icing is presented. Three possible forms of mass depositions are included in the model: freezing of surrounding water on the whole trash rack surface (glaze ice), accretion of floating frazil particles on the upstream part, and water inclusion in the accreted frazil ice matrix. Glaze ice will form on any obstacles placed in a water flow, provided the water is supercooled. The equilibrium temperature of the water is calculated by the model as a function of environmental parameters. For normal supercooling (some hundreds degree below zero) the accretion of frazil ice is much larger than glaze ice accretion. The largest contribution to the mass deposit is, however, from the occluded water. The results of several sensitivity analysis are presented, both for the residual water temperature, water surface heat fluxes and mass and maximum thickness of deposited ice on trash rack elements. The residual water temperature, and hence the glaze ice accretion, is very much affected by frazil concentration variations. In fact, for low number concentration (below about 4x10^5 per cubic meter) glaze ice accretion dominates due to the high degree of supercooling.
Year: 1994