LATTICE BOLTZMANN SIMULATION OF HEAT TRANSFER ENHANCEMENT DURING MELTING BY USING NANOPARTICLES

This research paper provides a mathematical modeling of heat transfer enhancement during melting process in a square cavity through dispersion of nanoparticles. The enthalpy-based lattice Boltzmann method (LBM) with a combination of D2Q9 and D2Q5 lattice models is used to solve density, velocity and temperature fields. The nano-enhanced phase change material (NEPCM) is composed of a dilute suspension of copper particles in water (ice) and is melted from the left. Also, in this study the sub-cooling case is neglected. Conduction heat transfer has been taken into account in the solid phase as well as natural convection in the liquid phase. Numerical simulations are performed for various volume fractions of nanoparticles and Rayleigh numbers ranging from 10^4 to 10^6. The validation of results is carried out by comparing the present results of natural convection and convection-dominated melting in a square cavity with those of existing earlier numerical studies. Predicated results illustrate that by suspending the nanoparticles in the fluid the thermal conductivity of NEPCM is increased in comparison with PCM. Also, by enhancing thermal conductivity and decreasing latent heat of fusion higher rates of heat release can be obtained.