Numerical analysis of mono and hybrid nanofluids-cooled micro finned heat sink for electronics cooling-(Part-II)

This study investigates the thermal and hydraulic performance of heat sinks with micro pin-fins in circular and rectangular configurations using mono and hybrid nanofluids. Motivated by the need for efficient cooling solutions in high-performance electronic devices, the research explores novel combinations of metallic oxide (Ag, MgO) and carbon-based nanoparticles (GNP, MWCNT) in nanofluids. A constant volume fraction of micro pin-fins and nanoparticles was maintained to assess their effects on thermohydraulic performance. The method involved experiments with aqueous nanofluids as coolants, measuring pressure drops ($\Delta p$) at the inlet and outlet. Thermal performance was evaluated using metrics like thermal resistance ($R_{\mathrm{th}}$), Nusselt number ($N{u}_{\mathrm{avg}}$), pumping power ($\mathrm{PP}$), volumetric flow rate ($Q$), overall performance ($\mathrm{OP}$), and performance evaluation criterion ($\mathrm{PEC}$). Results showed that GNP-based mono nanofluids significantly reduced $R_{\mathrm{th}}$ by 46.41% and increased $N{u}_{\mathrm{avg}}$ by 60.54% and PEC by 62% in rectangular heat sinks compared to conventional water cooling. Comparisons between rectangular and circular configurations revealed minimal $R_{\mathrm{th}}$ differences of 2.54% and 3.57%. GNP-dispersed nanofluids outperformed other coolants, with the rectangular configuration achieving a higher $\mathrm{PEC}$ of 1.62 versus 1.52 for the circular configuration at Δp = 820 Pa. The conclusions suggest that rectangular pin-fins with GNP-based nanofluids offer superior thermohydraulic performance. The key outcomes from current study have significant contribution in enhancing the cooling efficiency of advanced electronic systems.