Numerical investigation on the natural convection effects in the melting process of PCM in a finned container using lattice Boltzmann method

Abstract

This work presents a numerical study to investigate the melting process inside a finned rectangular container of phase change material. This issue is interested to know what will happen in the presence of fins, which increase the rate of heat transfer and immerse the solid body through the liquid phase. Momentum exchange between the liquid and solid phases necessitates to consider the immersed boundary condition on the solid–liquid interface. This procedure is done by considering the direct-forcing scheme in the lattice Boltzmann framework. In this regard, velocity and temperature fields are obtained using the multi relaxation time model. To track the solid–liquid interface, a set of Lagrangian points is intended on the boundary of the solid phase. Also, the phase change process is modeled by applying the energy conversion on the finite control volume around these points. Results include melting process for three states: assumption of pure conduction, considering the effects of natural convection around the fixed solid body and natural convection through the free solid phase. Comparing results of melting history and solid–liquid interface position in those states specifies the importance of momentum exchange between solid and liquid phases, in which the forced exerted by the fluid flow accelerates the melting process.