Numerical solution of rapid freezing of sea water on cold substrates

Rapid freezing of sea water on a cold substrate of spongy ice is investigated. The mechanism of transient ice accretion on cold substrates is different than slow freezing of salt water. An investigation of rapid freezing in this paper fills a gap of knowledge related to periodic icing of salt water on marine and offshore structures. The equation of transient heat conduction through brine-spongy ice is analyzed. Rapid freezing causes complete salt trapping, which makes the salinity constant and stable at the phase interface during the solidification. A thin layer of salt water is considered in contact with a spongy substrate. A finite difference method is employed to calculate the rate of solidification of the brine layer and consequently the thickness of ice accumulated. The discretization is based on the Method of Lines (MOL) which is a useful numerical-iterative method for boundary moving problems. Numerical results show that colder substrates and brine layers have the potential to create a thicker layer of new ice.