Thermal conductivity and heat capacity of water/Iβ cellulose nanofluids: A molecular dynamics study

Abstract

Cellulose nanofluids have a great application potential in the energy industry, and their thermal properties are substantially affected by the components and microstructures of nanofluids. Therefore, this study investigated the isobaric heat capacity and thermal conductivity of cellulose I[Formula: see text] nanofluids mixing with H2O by molecular dynamics (MD). The results showed that the existence of water in cellulose increased the isobaric heat capacity of the system, especially for the random cellulose/H2O nanofluids. Additionally, nonequilibrium molecular dynamics (NEMD) simulations based on the Fourier law of thermal conduction were conducted to examine the thermal conductivity of the simulated systems. As indicated by our results, the cellulose I[Formula: see text] crystal was advantageous in terms of its high directional thermal conductivity along the chain direction. Thus, the thermal conductivity of the cellulose/H2O nanofluids along the chain direction used the high directional thermal conductivity of the cellulose I[Formula: see text] crystal. Consequently, the cellulose/H2O nanofluids integrated the superiorities of high isobaric heat capacity of water and great directional thermal conductivity of cellulose I[Formula: see text] crystal, thereby improving the heat transfer efficiency in thermodynamic systems. In addition, the potential energy of the cellulose crystal system was mainly generated by intermolecular repulsion, while those of the cellulose/H2O nanofluid systems were mainly produced through intermolecular attraction.