The use of molecular dynamics method to evaluate the thermo-physical properties of Cu nanoparticles dispersed in Paraffin wax PCM

Background

One of paraffin wax's most significant practical applications is for thermal energy storage (TES). Phase change materials (PCMs), such as paraffin wax, are being investigated to store thermal energy in various applications, from building heating and cooling systems to solar power plants. Adding copper nanoparticles (NPs) to the paraffin wax can enhance the mixture's performance. Another potential application of the paraffin wax-copper nanofluid model is in the development of advanced cooling systems.

Methods

The present research aims to evaluate the effects of different panel temperatures (Temps) on the thermal performance (TP) and electrical efficiency (EE) of paraffin wax-Cu nanofluid (NF) between parallel plates via the Molecular Dynamics (MD) method by using the LAMMPS simulation software.

Significant Findings

As the simulation progresses, the atomic structure undergoes significant changes in energy and TP. The potential energy (PE) decreases and stabilizes at -12,444.55 eV after 100,000 time steps, while the kinetic energy (KE) reaches a steady value of 763.51 eV. The nanoparticles (NP) in the middle of the wall exhibit the highest velocity, peaking at 0.002 Å/ps, and the maximum Temp is recorded at 334.08 K in the wall's center. Over time, the structure's TC stabilizes at 0.3199 W/m.K after 2 ns. However, increasing the wall Temp from 300 K to 400 K leads to an increase in nanoparticle velocity, from 0.02 Å/ps to 0.0283 Å/ps, and raises the maximum Temp from 334.08 K to 406.05. This temp rise also slightly improves the TC from 0.319 W/m.K to 0.325 W/m.K, but it causes a significant 84 % decrease in EE, highlighting the critical impact of Temp on the structure's behavior.