Synthesis, Characterization and Application of Nanofluid— An Overview

Abstract

Nanofluids are quasi single phase medium containing stable colloidal dispersion of ultrafine or nanometric metallic or ceramic particles in a given fluid. Despite almost a negligible concentration (< 1 vol%) of the solid dispersoid, nanofluids register an extraordinarily high level of thermal conductivity, which largely depends on identity (composition), amount (volume percent), size and shape of the dispersoid and viscosity, density and related thermo-physical parameters of the base fluid. Nanofluids possess immense potential of application to improve heat transfer and energy efficiency in several areas including vehicular cooling in transportation, power generation, defense, nuclear, space, microelectronics and biomedical devices. In the present contribution, a brief overview has been presented to provide an update on the historical evolution of this concept, possible synthesis routes, level of improvements reported, theoretical understanding of the possible mechanism of heat conduction by nanofluid and scopes of application. The overview is supplemented with a summary of recent results from the author’s own group to highlight certain simple approaches of synthesis and extent of enhancements achieved with those indigenous efforts. The biggest motivation for exploration and exploitation of nanofluid should come from the fact that the degree of consistently attained enhancement of thermal conductivity far exceeds the level predicted by the existing theory on the subject.