Melting process with solid-liquid density change and natural convection in a rectangular cavity

• Published in: The International journal of heat and fluid flow 1991, Vol.12 (4), p.365-374
• Main Authors: Yoo, Hoseon, Sung Tack, Ro
• Format: Article
• Language: English
• Subjects: boundary-fitted coordinate system; convection; density; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Heat transfer; Heat transfer in inhomogeneous media, in porous media, and through interfaces; phase-change problems; Physics; solid-liquid density change; two phase flow
• ISSN: 0142-727X; 1879-2278
• DOI: 10.1016/0142-727X(91)90026-R

This paper presents a numerical method that simulates the melting process in the presence of solid-liquid density change and natural convection in the melt. The physical model concerned is two-dimensional melting of a phase-change material, initially at its fusion temperature, charged in a rectangular cavity with isothermally heated side walls and an adiabatic bottom wall. The presence of the density change brings no change into the basic form of governing equation, so it is considered through the reformulation of boundary conditions. Difficulties associated with the complex time-dependent melt region, whose shape is also a part of the solutions, are overcome by employing the boundary-fitted coordinate system. Comparison with other works validates the present numerical model and reveals the effects of density change qualitatively. Also, it is confirmed that the present method is preferable to others with natural convection only. Computed results for interesting cases are shown in forms of transient position of the interface, temperature distribution, flow pattern, heat transfer coefficient, and melting fraction as a function of time. Closer examination on melting patterns allows a correlation to be made between the melting fraction and a new independent variable Ste· Fo· Ra 1 4 .