Numerical and Experimental Analysis of Hybrid Micro-Baffle Heat Sinks Employing Multi-Walled Carbon Nanotube (MWCNT) Water-Based Nanofluids for High-Flux Thermal Management

Abstract

Modern power electronic devices, high-frequency radar modules, and concentrated photovoltaics generate extreme localized heat fluxes exceeding 250?" W/cm" ?^2. Standard microchannel cooling systems often encounter thermal saturation along the length of the channel, leading to non-uniform temperature profiles and high thermal stresses across chip substrates. This paper presents a comprehensive computational and experimental study of a hybrid microchannel heat sink (HMHS) equipped with micro-baffles operating with multi-walled carbon nanotube (MWCNT) water-based nanofluids (0.05" vol" %" to " 0.3" vol" %). The angled micro-baffles periodically break the hydrodynamic boundary layer and induce secondary convective mixing. Conjugate heat transfer simulations, validated against experimental measurements, demonstrate that using a 0.2" vol" %" MWCNT-water" nanofluid at Re=1100 reduces total thermal resistance by 39.5% compared to pure water in smooth channels. The average Nusselt number increases by 54.8%, accompanied by a 16.2% pressure drop penalty. The maximum temperature variation across the substrate is limited to 3.2" K" , mitigating localized thermal hot spots. Detailed parametric analyses, boundary dynamics, limitations, and future research opportunities are presented.

KEYWORDS: Microchannel Heat Sink, Carbon Nanotubes, Micro-Baffles, Electronics Cooling, Conjugate Heat Transfer, Pressure Drop