Investigating the initial pressure effect on Brownian displacement, thermophoresis, and thermal properties of graphene/ water nanofluid by molecular dynamics simulation

Abstract

The concept of nanofluid includes suspensions containing nanoparticles, metallic and non-metallic materials. Nanofluids have many potentials in different environments and conditions that make them exist in industries and food industries. Considering their high thermal conductivity, the nanoparticles increased the fluid's thermal conductivity, one of the basic heat transfer parameters, when distributed in the base fluid. The present research investigated the thermal properties, Brownian motion, and thermophoresis of water/ graphene nanofluid affected by different ratios of initial pressure (1, 2, 3 and 5 bar) by molecular dynamics simulation. This study reported the changes in heat flux, thermal conductivity, average Brownian displacement, and thermophoresis. The results depict that by increasing the initial pressure from 1 to 5 bar, average Brownian displacement and thermophoresis values decrease from 06.3 and 23.88 to 2.91 and 23.53 angstrom, respectively. Also, by raising the initial pressure (1 to 5 bar), the heat flux and thermal conductivity after 10 ns decrease from 39.54 and 0.36 to 35.12 W/m2 and 0.28 W/m.K, and the maximum temperature reduces from 1415 K to 1033 K. These results can be useful in different industries, especially for improving the thermal properties of different nanofluids.