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A numerical study is reported of natural convection melting of ice within a vertical cylinder. A stream function‐vorticity‐temperature formulation is employed in conjunction with body‐fitted coordinates for tracking the irregular shape of the timewise varying solid‐liquid interface. A parabolic density profile versus temperature is assumed for water. Numerical experiments are carried out for a temperature of the cylinder wall ranging from 4°C to 10°C. Results show that natural convection heat transfer involving density anomaly leads to complex flow patterns and strongly affects the time evolution of the phase front. The maximum Nusselt number at the heated cylinder wall is obtained for Tw = 4°C while the minimum is observed for Tw = 8°C.

Melting of pure metal in presence of turbulent natural convection with Rayleigh number ranging from 106 to 109 has been studied numerically. The governing equations are formulated in terms of stream function—vorticity—temperature and the moving distorted solid/liquid interface is tracked using body‐fitted coordinates. The turbulent flow is taken into account using an algebraic eddy‐viscosity model with Prandtl's mixing length. Results indicate that turbulent natural convection plays a more significant role than laminar flow in the process of melting. Heat transfer and melting rates are significantly increased and a correlation for the average Nusselt number at the heated wall in the quasi‐steady melting regime is proposed.