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

Abstract

This research paper provides a mathematical modeling of heat transfer enhancementduring melting process in a square cavity through dispersion of nanoparticles. The enthalpy-basedlattice Boltzmann method (LBM) with a combination of D2Q9 and D2Q5 lattice models is used tosolve 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 fromthe left. Also, in this study the sub-cooling case is neglected. Conduction heat transfer has beentaken into account in the solid phase as well as natural convection in the liquid phase. Numericalsimulations are performed for various volume fractions of nanoparticles and Rayleigh numbersranging from 104 to 106. The validation of results is carried out by comparing the present results ofnatural convection and convection-dominated melting in a square cavity with those of existingearlier numerical studies. Predicated results illustrate that by suspending the nanoparticles in thefluid the thermal conductivity of NEPCM is increased in comparison with PCM. Also, byenhancing thermal conductivity and decreasing latent heat of fusion higher rates of heat releasecan be obtained.