Effect of Microchannel Aspect Ratio on Laminar Nanofluid Flow and Thermal Performance: A Three-Dimensional Numerical Study

Saleh Etaig, Nabil Elsharif

Abstract

Microchannel heat sinks have emerged as an effective thermal management solution for compact electronic and energy systems subjected to high heat fluxes. In parallel, nanofluids have been proposed as advanced working fluids capable of enhancing convective heat transfer due to their improved thermophysical properties. In this study, a three-dimensional numerical investigation of laminar nanofluid flow and heat transfer in rectangular microchannels is conducted with a focus on the combined effects of geometric and operating parameters. An Al₂O₃–water nanofluid is employed as the working fluid and modeled as a homogeneous single-phase Newtonian fluid. The governing equations of mass, momentum, and energy conservation are solved using the finite volume method under steady-state conditions. Uniform heat flux is applied to three channel walls, while the remaining wall is assumed adiabatic. The influence of microchannel aspect ratio, hydraulic diameter, and Reynolds number on velocity distribution, temperature fields, and Nusselt number is systematically examined. The results indicate that Reynolds number is the dominant parameter controlling convective heat transfer enhancement, while increasing hydraulic diameter and aspect ratio generally reduce thermal performance under laminar conditions. The findings provide design-oriented insights for efficient rectangular microchannel heat sinks employing nanofluids in advanced thermal management applications.

Keywords

Microchannel heat sink, Nanofluid, Numerical investigation, Convective heat transfer, Laminar flow

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References

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