Computational investigation of the influencing parameters on the melting of phase change material in a square enclosure with built in fin and Al2O3 nanoparticles

Abstract

Recent advances in renewable energy resources set the interesting research development in the thermal energy storage concepts. The thermal energy storage system (TES) stores the thermal energy in the form of sensible or latent heat or by chemical exothermic and endothermic reactions. In this work, a numerical analysis is implemented to study the effect of Grashof number (Gr), simultaneous incorporation of longitudinal fin, and nanoparticles addition on the transfer of heat and rate of melting of phase change material (PCM). The variation in the position of the fin (0.25H, 0.5H, and 0.75H), length of the fin (0.25L, 0.5L, and 0.75L) relative to the height and length of the container respectively, and different concentrations of Al2O3 nanoparticles (0%, 1%, 3%, and 5%) were studied. The high temperature heat source is given to the left side of the wall, and the low temperature sink condition is applied to the right side. The analysis is carried out for three Gr (5000, 13000, and 20000). It is noted that the time of melting is reduced with longer lengths of the fin and Gr. Also, the melt fraction increases with the position and volume fraction of the nanoparticles up to a certain limit after it reduces. The fin’s optimum length and position were selected as 0.5H and 0.75L with 4.99% and 2.03% more liquid fraction than the other positions. Also the favourable nanoparticles concentration is adopted as 3% Al2O3 with an increase of 5.04%, 4% and 2.56% of melt fraction more than the pure PCM, PCM + (1% Al2O3) / (5% Al2O3) respectively.