Melting heat transfer of power-law non-Newtonian phase change nano-enhanced n-octadecane-mesoporous silica (MPSiO2)

The heat transfer removal from heated elements in different engineering devices is the main challenge for each engineer in various fields. This problem can be solved using an effective heat-transfer agent or by increasing the heat transfer surface. The present work is devoted to an opportunity to use the phase change material with nanoparticles for an intensification of heat removal within a gap between two coaxial vertical isothermal cylinders. The analysis was performed numerically using the Galerkin finite element approach in the case of the non-Newtonian nature of the nano-enhanced PCM. The power-law was used for the description of the non-Newtonian behavior of the considered material. For the solution to the Stefan problem, a deformed mesh method, based on the Arbitrary Lagrangian-Eulerian (ALE), was used. The developed computational code was validated using the numerical and experimental data of other authors. The effects of the nanoparticles volume fraction, aspect ratio and Fourier number on the melting process were investigated. It has been revealed that the inclusion of nanoparticles within the phase change material leads to both less intensive melting of the material and a reduction of the average Nusselt number. (C) 2020 Elsevier Ltd. All rights reserved.