Abstract:
Electrophoresis has been shown as a novel methodology to enhance heat conduction capabilities of nanocolloidal
dispersions. A thoroughly designed experimental system has been envisaged to solely probe heat
conduction across nanofluids by specifically eliminating the buoyancy driven convective component. Electric
field is applied across the test specimen in order to induce electrophoresis in conjunction with the existing
thermal gradient. It is observed that the electrophoretic drift of the nanoparticles acts as an additional thermal
transport drift mechanism over and above the already existent Brownian diffusion and thermophoresis dominated
thermal conduction. A scaling analysis based on the thermophoretic and electrophoretic velocities from
classical Huckel-Smoluchowski formalism is able to mathematically predict the thermal performance enhancement
due to electrophoresis. It is also inferred that the dielectric characteristics of the particle material is the
major determining component of the electrophoretic amplification of heat transfer. Influence of surfactants has
also been probed into and it is observed that enhancing the stability via interfacial charge modulation can in fact
enhance the electrophoretic drift, thereby enhancing heat transfer calibre. Also, surfactants ensure colloidal
stability as well as chemical gradient induced recirculation, thus ensuring colloidal phase equilibrium and low
hysteresis in spite of the directional drift in presence of electric field forcing. The findings may have potential
implications in enhanced and tunable thermal management of micro-nanoscale devices and in thermo-bioanalysis
within lab-on-a-chip devices.
