Thermophoretically driven capillary transport of nanofluid in a microchannel

TL;DR

This study models how thermophoretic forces and temperature-dependent viscosity influence nanofluid capillary filling in microchannels, revealing thermal gradients can significantly control particle transport and retention.

Contribution

It introduces a comprehensive model accounting for thermofluidic coupling and particle size effects on nanofluid transport in microchannels under thermal gradients.

Findings

Thermophoretic force enhances capillary filling efficiency.

Thermal gradients reduce particle retention in nanofluids.

Viscosity variation with temperature significantly affects flow dynamics.

Abstract

We investigate the interplay of thermophoretic force and interfacial tension on the capillary filling dynamics of a Newtonian nanofluid in a microchannel. In our model, we also consider an intricate thermofluidic coupling by taking the temperature dependence of viscosity aptly into account. This, in turn, determines the evolution of the viscous resistive force as the capillary front progresses, and presents an involved inter-connection between the driving thermophoretic force and the viscous resistive force. The two distinct regimes of particle transport in a fluid medium, delineated by particle size, are expounded to peruse the impact of imposed thermal gradients and particle size on particle retaining propensity of the nanofluid. Additionally, we witness a significant reduction in particle bearing proclivity of the nanofluid with enhancement in a thermal gradient. The results demonstrate the efficacy of the thermophoretic actuation towards the filling of narrow capillaries under the influence of a thermal gradient.