A numerical study of solidification of n-hexadecane based on the enthalpy formulation

Abstract

A numerical study is described in this paper on the investigation of the solidification of a pure n-hexadecane inside a rectangular enclosure based on an enthalpy formulation of the energy equation. A vertical wall of the enclosure is maintained at a constant temperature below the melting temperature of the n-hexadecane while all other sides are adiabatic. The effects of the cold wall temperature, initial liquid superheat and aspect ratio of the enclosure are studied in terms of the solid fraction and the shape of the solid–liquid phase front. It has been found that a lower wall temperature and a smaller initial liquid superheat result in a larger solid fraction. The solidification process is more affected by the natural convection at the early stage of the solidification than at the later stage. This is inferred by the reduction in the phase front’s slope with time as the temperature in the liquid becomes more uniform. At the early stage of the solidification where natural convection is more dominant in the liquid, a lower wall temperature and a larger liquid superheat result in a larger slope on the phase front, indicating strong natural convection in the liquid. The aspect ratio of the enclosure has some effect on the shape of the phase front, but has only a weak effect on the solid fraction.