Flow behaviors of nanofluids in parallel-plate nanochannels influenced by the dynamics of nanoparticles

The flow behaviors of the copper (Cu) - argon (Ar) nanofluids (NFs) confined in the parallel-plate nanochannels are investigated by using molecular dynamics (MD) simulations. Through exploring the dynamics of the Cu nanoparticles (NPs), the internal shear stress and the velocity profiles of NFs in both the Couette and Poiseuille models, the flow mechanism of the NFs confined in nanochannels is deeply reassessed associated with the nanoscaled configurations of the NFs. The results reveal that the flow behavior of the Cu-Ar NFs is dramatically sensitive to the morphology of the Cu NPs. The accumulated NPs can induce the fluctuation of the shear stress profiles at the corresponding locations in channel width direction. The increase in the volume fraction of NPs increases the chance of the Cu NPs adsorbing on the solid walls, whereas the NPs adsorbed on the solid walls can hinder the boundary slip and further decrease the volumetric flow rate. An accumulated NP cluster within the NFs away from the channel walls does not change the overall viscosity of the NFs while it can increase the volumetric flow rate attributed to the increase of the overall density of the NFs in Poiseuille model. Nevertheless, the dispersed Cu NPs within the NFs can increase the viscosity of the NFs, and further decrease the flow rate of the Poiseuille flows for the identical driving acceleration.