Analysis of Fluid Flow and Heat Transfer Inside a Spherical Container Encapsulated by Molten Salt
Abstract
A mathematical model of melting process inside a spherical container, which is filled with phase change material, is developed to describe the characteristics of heat transfer and flow inside the capsule for high temperature storage systems. The finite element method is used to solve continuity, momentum and energy equations. The main intention of this investigation is to derive a dimensionless correlation for effective thermal conductivity. The correlation can be used in packed bed models to study the thermal performance of the thermal energy storage systems. The capsule is filled with sodium nitrate since its melting point is in the operation range of concentrated solar power plant. The shell of the capsule is made up of nickel, which is uniformly heated at the external surface. The enthalpy-porosity method is used to track the solid-liquid interface. The model is, validated with the reported experimental results, used to investigate the influence of pellet size and Stefan number.
Keywords
Thermal energy storage system, latent heat, melting of pcm, effective thermal conductivity