Molecular Dynamics Simulation of Thermal Behavior of Paraffin/Cu Nanoparticle PCM in a Non-Connected Rotating Ribbed Tube

Abstract

Applying molecular dynamics simulations, this study investigates the influence of different atomic ratios of Cu nanoparticles on the atomic and thermal behavior of a paraffin/Cu composite within a non-connected rotating ribbed tube. A simulation box measuring 50 x 150 x 50 & Aring;3 is employed, with periodic boundary conditions in y and z-coordinates. LAMMPS simulation is running for a total of 20 ns. The simulation model is validated through an equilibration phase for 10 ns, achieving a temperature of 300 K and a total energy of 1.450 kcal/mol. The results indicate that the maximum density decreases to 0.0852 atom/& Aring;3 as the atomic ratio of Cu nanoparticles increases from 1 to 7 %. Additionally, the velocity and temperature increased to 0.00493 & Aring;/fs and 766 K. Furthermore, the thermal conductivity increased from 0.63 to 0.68 W/m & sdot;K, and the heat transfer increased from 5.25 to 5.36 W/m2. The charging and discharging times decrease to 6.24 and 7.11 ns. These trends are reversed at an atomic ratio of 10 %: the maximum density increased, the velocity and temperature decreased, the heat flux and thermal conductivity decreased to 5.33 W/m2 and 0.67 W/m & sdot;K, and the charging/discharging times increased to 6.26 ns and 7.18 ns, respectively. These results indicate that an optimal concentration of 7 % Cu nanoparticles improved thermal conductivity. The paper examined the influence of nanoparticle saturation on thermal stability, demonstrating that excessive agglomeration adversely impacts heat conduction. This study offered for the development of superior nanoparticle-enhanced phase change materials in confined systems with unconnected rotating ribs, to improve heat dissipation and stability.