Local thermal nonequilibrium conjugate natural convection of nano‐encapsulated phase change particles in a partially porous enclosure

Abstract

This paper analyzes the heat transfer process of nano‐encapsulated phase change material (NEPCM) particles suspended in a base fluid. NEPCMs are polyurethane‐nonadecane, and the base fluid is water. The formed suspension fills a system of two different layers: a porous layer and a clear layer. A thermally conductive solid wall transmits heat to the porous layer. These three partitions are confined in a square cavity. The cavity is heated from the left side of the solid wall and cooled from the right side of the clear layer. The solid matrix of the porous layer and the suspension are in local thermal nonequilibrium. A Galerkin‐weighted residual finite element method is adopted for numerical computations. The impacts of Stefan number, fusion temperature, and the nanoparticles volume fraction are inspected, graphically. Results show that the maximum heat transfer can be attained with lower Stefan number, higher nanoparticles volume fraction, and a fusion temperature range between 0.2 and 0.6. For a certain circumstance, it is found that enhancement of about 29% in heat transfer can be gained when the volume fraction of the NEPCM particles is raised from 0 to 0.05.