Fins Arrangements and Al2O3 Nanoparticles Concentrations Effects on Melting Time of RT82 Paraffin PCM in Double-Pipe Heat Exchanger

The current study includes the numerical modeling of a Double-Pipe Heat Exchanger containing a phase change material mixed with Al₂O₃ nanoparticles at different fins configurations. The objectives of this study are the determination of the effect of nanoparticles on the melting process of PCM and evaluating the melting time for different configurations of copper fins through the heat exchanger. The numerical study used COMSOL Multiphysics based on the enthalpy method. Paraffin RT82 was used as a phase change material with aluminum oxide nanoparticles (Al₂O₃). The results showed that the number of fins leads to a faster and more efficient melting process compared to a heat exchanger that does not contain fins. However, this reduces the amount of PCM present inside the annular domain, and thus the amount of heat stored decreases. The time of full melting of the PCM was equal to 193.96 min, while the time decreased to reach 187.5 and 181.46 min when the nano concentration was increased to 4% and 6%, respectively. The third case contributed to saving 31.89% of the melting time, followed by the seventh case by 27%, while the second and fifth cases were the least effective by 9.4% and 10.52%, respectively.