Numerical Investigations of MWCNT Nanofluid Cooling in Pinfin Enabled Microchannel Heat Sinks

A numerical investigation was carried out to analyze the thermal and hydraulic performance of microchannel heat sinks (MCHSs) with varying pin heights (6.2 µm, 18.6 µm, 31 µm, and 43.4 µm) using MWCNT/water nanofluids for different volume concentrations. Simulations were performed under steady laminar flow conditions to evaluate temperature distribution, Nusselt number (Nu), friction factor (f), and thermal performance factor (TPF). Results revealed that both increasing pin height and nanofluid concentration enhanced heat transfer due to improved mixing and higher thermal conductivity. However, taller pin fins caused higher pressure drops, reducing overall hydraulic efficiency. Among all configurations, the 6.2 µm pin height with 2.5% MWCNT nanofluid pulled off the best balance between heat transfer and flow resistance, exhibiting the highest TPF across all velocities. This indicates that moderate fin height and optimal nano-particle concentration significantly improve thermal performance without excessive pumping penalties. The optimized configuration is highly compatible for compact electronic cooling and microscale thermal management systems, where efficient heat removal and minimal energy loss are indispensable.