Molecular dynamics approach to study the effects of MgCl2 salt atomic ratio on the phase transition phenomenon in the phase change materials

Abstract

In general, phase change materials reduce energy consumption in different structures by increasing the thermal conductivity or decreasing the phase change time. On the other hand, hydrated salts are the most important group of phase change materials with high phase change temperatures and are extensively studied in latent thermal energy storage systems. Today, these atomic structures are used in different usages such as thermal transfer compounds, commercial and industrial applications, for cooling and heating on a small scale, etc. In the current computational study, we utilized Molecular Dynamics procedure to explain the thermal and phase transition (from liquid to solid-state) behavior of water liquid in the presence of MgCl2 salt as salts hydrate compound. Computationally, physical parameters like temperature, potential/total energy, phase transition time, thermal conductivity, and velocity/density profile of H2O-MgCl2 nanofluid were reported for time=15 ns. Molecular Dynamics outputs indicated that the phenomenon of phase transition in simulated nanofluid happens in a shorter time using a 4% atomic ratio salt structure. This atomic behavior of simulated structure causes thermal behavior improvement is defined nanofluid. Numerically, by MgCl2 salt ratio optimizing, H2O-MgCl2 nanofluid thermal conductivity converged to 0.67 W/m.k. Technically, thermal conductivity calculation in current research is done by using the Green-Kubo method.