Molecular dynamics investigation of ionanofluids (INFs): Towards a deeper understanding of their thermophysical, structural and dynamical properties

Abstract

Ionanofluids (INFs) are a novel type of heat transfer fluids consisting of fine nanoparticles suspended in ionic liquids (ILs). They exhibit improved thermal properties, including enhanced thermal conductivity, non-volatility, and non-flammability, making them ideal candidates for various applications, especially solar concentrators. In this work, for the first time, molecular dynamics (MD) simulations are used to investigate the thermophysical, structural, and dynamical properties of a specific INF composed of the [HMIM][BF4] IL and SiC nanoparticles in the temperature range of 298.15–338.15 K and at different nanoparticle volume fractions, i.e. 1.10 %, 2.27 %, and 3.47 %. Radial distribution functions (RDFs) revealed a strong structural correlation between the fluorine atoms of anion and the HR atom of the cation ring and also with the carbon and silicon atoms of the nanoparticle. The results showed that with increasing the volume fraction of nanoparticles, ions tend to have more interactions with nanoparticles, and the interactions between the anions and cations decrease. As a result, the thermal conductivity, viscosity, and density of ions in the INF increases. Finally, we made some comparisons between the simulated thermal conductivities and viscosities of the studied INF with classical models. The results showed that, in some cases, the simulation results were even better than some models compared to the experimental values. The insights obtained from this study not only enhance our understanding of the structure and dynamic behavior of the INF, but also can contribute to the development of innovative materials and more efficient solar thermal systems.