Motion of Nanoparticles in Nanofluids Under an Electric Field

Abstract

Nanofluids — fluids with unprecedented stability of suspension nanoparticles — have attractive features such as high thermal conductivities at very low nanoparticle concentrations, strongly temperature-dependent conductivity, and three-fold higher critical heat flux compared to base fluids. These features are not explained by traditional theories of solid/liquid suspensions, such as Maxwell’s theory or other macroscale approaches. Recently, Jang and Choi’s model has led to the discovery, primarily by extending Einstein’s theory of Brownian motion to energy transport in nanofluids, that Brownian motion of nanoparticles at the molecular and nanoscale level is a dominant mechanism governing their thermal behavior. In this paper we describe a theoretical model for controlling the motion of nanoparticles in nanofluids by means of an electric field and an analytical solution for particle motions in nanofluids. We show that the motion of nanoparticles can be controlled by use of an AC field and that the size and zeta potential of the nanoparticles are the key parameters to control nanoparticle motion beyond Brownian motion.