High Rayleigh Number Solutions to Problems of Latent Heat Thermal Energy Storage in a Horizontal Cylinder Capsule

Abstract

An analysis was made of the melting and solidification heat transfer inside a horizontal circular cylinder capsule in which n-octadecane or water was used as a phase change material. Special efforts were made to obtain solutions with high Rayleigh numbers (i.e., for large diameters). To this end, the following three tools had been adopted: (i) To save computation time, a high-accuracy, multipoint, explicit finite difference scheme was adopted; (ii) To eliminate complex moving boundaries, two-dimensional Landau transformation was adopted; (iii) To suppress the strong numerical instability, a smoothing technique using the least square method of the sixth order was devised. Transient aspects for natural convection flow, temperature profiles, and melting interfaces were clarified in detail. It is especially noted that entirely different results from those of Pannu et al. were obtained.