Effect of chaotic movements of nanoparticles for nanofluid heat transfer augmentation by molecular dynamics simulation

•The orders of magnitude of translational and rotational motions for nanoparticles are given.•The microscopic structure around a nanoparticle is proposed.•Mechanisms of heat transfer enhancement in nanofluids are discussed.

Through Molecular Dynamics simulation, the chaotic movements of nanoparticles in base fluid are investigated. Based on the simulated results of translational and rotational velocities of nanoparticles, the effect of nanoparticle movements for heat transfer in nanofluids is discussed. Furthermore, the influence of nanoparticle movements for the base fluid is studied. The fluid near a nanoparticle is divided into three levels: (1) absorption layer, (2) rotating fluid, and (3) spherical existential space, or called rotating fluid element. And the microscopic structure of nanofluid which is composed of countless rotating fluid elements is proposed.