Modeling of icing on a planar surface due to Sea spray and blowing Snow

Abstract

Two main extensions of the time-dependent two-dimensional sea spray icing model ICEMOD2.1 (Horjen, 2015) is presented. The first extension, called ICEMOD2.2, is the inclusion of heat conduction through the accreted ice. This quantity has been calculated from the temperature distribution in the ice which varies with time. The second extension, called ICEMOD2.3, is the combined effect of sea spray and snow. No other icing models have ever before included this effect. The new models have been applied for some reported icing cases on the nearly vertical wall of the bulkhead of the large Norwegian coast guard vessel KV Nordkapp from 1983 to 1997. Local wind field above the boundary layer, heat loss by forced convection and wind stress have been approximated by using analytical formulas for the wind field around a single plate. The physics of instantaneous freezing of a fraction of supercooled droplets upon impact has been discussed and implemented in the model.The most severe icing conditions in Norwegian Arctic water often occur during polar lows, which are often followed up with heavy snow fall. Due to the inclusion of snow the thermal conductivity of the ice accretion is modified. Using an electrical analogy it is shown that this parameter decreases during snow conditions. Overall ice salinity and density are also affected by the snow.