Effect of Nanoconvection due to Brownian Motion on Thermal Conductivity of Nanofluids

Abstract

A nanofluid is a new class of heat transfer fluids that contain a base fluid and nanoparticles. The use of additives is a technique applied to enhance the heat transfer performance of base fluids. The thermal conductivity of the ordinary heat transfer fluids is not adequate to meet today's cooling rate requirements. Nanofluids have been shown to increase the thermal conductivity and convective heat transfer performance of the base liquids. One of the possible mechanisms for anomalous increase in the thermal conductivity of nanofluids is the Brownian motions of the nanoparticles inside the base fluids. It is shown in this Study that the heat diffusion assumption that has been used in the macro- and micro- composite systems is not valid in the nanofluid systems. Apart from heat diffusion the nanoconvection diffusion that it is due to the indirect effect of Brownian motion is responsible of enhancement in thermal conductivity Of nanofluid systems.