Investigation of 2D Melting Process within a Porous Medium Considering Local Thermal Nonequilibrium Condition in the Presence of Sinusoidal Boundary Condition by Lattice Boltzmann Method

This paper investigates the local temperature difference between the phase change material and porous medium during the two-dimensional melting process by considering natural convection and applying sinusoidal boundary condition. Hence, the density distribution function is used to solve momentum equations and two separate distribution functions are used to solve energy equations to calculate the local temperature difference and liquid fraction of the phase change material. Also, the effect of parameters such as amplitude and frequency of oscillation and Sparrow number on the percentage of local temperature difference and comparison of liquid fraction in the presence and absence of natural convection, are studied. Results show that with increasing frequency from 1 to 3, the percentage of local temperature difference increased from 41.44% to 67.53%, and with increasing oscillation amplitude from 1 to 3, the percentage of local temperature difference is reduced from 41.44% to 20.56%. Also, by increasing the Sparrow number from 322 to 6000, the percentage of local temperature difference decreases from 41.44% to 4.21%. Also, it is observed that by changing oscillation frequency, liquid fraction does not change much compared to the conditions of pure conduction; however, as the amplitude of oscillation increases, the percentage of deviation of liquid fraction from the pure conduction increases.