Melting Process of Phase Change Materials in a Triplex-Tube: Arrangement, Newtonian and Non-Newtonian

In this paper, a numerical study is presented on the investigation of heat transfer and melting process of phase change material in a finned triplex tube. The non-Newtonian Power-Law model is used to simulate the non-Newtonian fluid and the enthalpy-porosity method is used to simulate the melting process. The results show that the melting process in the case of using Newtonian fluid is more than in the case of using non-Newtonian fluid. Thus, the average value of the melting fraction of the phase change material in 5000 seconds is about 3.03% higher for the Newtonian phase change material. The effect of the two-layer composition of the Newtonian & non-Newtonian phase change material and how they are placed in the middle and outer tubes on the melting process has been investigated. For this purpose, two arrangements have been considered according to the way the fluids are placed in the middle-outer tube: 1. Newtonian & non-Newtonian fluid and 2. Non-Newtonian fluid - Newtonian. The melting process for the Newton-non-Newtonian fluid state is faster than for the non-Newtonian-Newtonian fluid state. The melting fraction in the Newtonian & non-Newtonian fluid states is about 10.32% higher than in the other state. The amount of melting fraction decreases with increasing Consistency index and decreasing Power-law index. The Nusselt number changes are similar to the melting fraction changes.