Natural convection of rectangular cavity enhanced by obstacle and fin to simulate phase change material melting process using Lattice Boltzmann method

Abstract

In recent years, the lattice Boltzmann method has become a powerful method for computational modeling of various complex fluid flow concerns, including the simulation of the melting process in phase change materials. In the present paper, the natural convection of phase change materials in a cavity is simulated, and the effect of adiabatic obstacle and fin is investigated by the lattice Boltzmann method. The obtained results are presented in different Rayleigh numbers (Ra = 103-105), and cavity angles (θ=-90to90) in three scenarios (without adiabatic fin and obstacle, with an adiabatic obstacle, and with adiabatic fin). The investigation across various cavity angles, with adiabatic obstacles and fins, demonstrates a consistent trend of effective melting process delay by up to 50%, underscoring the significant impact of these adiabatic features on PCM behavior. Adiabatic obstacles induce localized melting delays due to unmelted zones around them. Streamlines highlight vortices formed by obstacles, and elevated Nusselt numbers correlate with accelerated melting facilitated by adiabatic fins. Modifying the adiabatic fin height from Yf = 0.1 to Yf = 0.7 leads to a doubling of melting time at around 80% PCM melting. Conversely, decreasing fin height from 0.5 to 0.7 extends the complete melting time by approximately 10%, showcasing the influential role of fin height in shaping PCM melting behaviour.

Keywords

• Lattice Boltzmann Method
• Phase change material
• Adiabatic fin
• Adiabatic obstacle
• Fluid fraction diagram