Enhancing thermo-hydraulic performance in flow boiling with hybrid nanofluids in double-layered wavy microchannel heat sink

This study uses water-based nanofluids to investigate the thermo-hydraulic performance of flow boiling in single-layer and double-layer wavy microchannels. A numerical analysis employing the Volume of Fluid-Discrete Phase Model (VOF-DPM) evaluates mono nanofluids (Al2O3, MWCNT, CuO, SiO2, TiO2) and hybrid nanofluids (MWCNT-TiO2, Al2O3-CuO, SiO2-CuO, MWCNT-Al2O3, SiO2-TiO2) across varying concentrations. Results identify 2 % nanoparticle concentration as optimal, with performance degradation at higher levels due to increased viscosity and nanoparticle agglomeration. MWCNT and MWCNT-TiO2 hybrid nanofluids demonstrate superior heat transfer performance among the tested fluids. The double-layer microchannel configuration significantly enhances heat transfer, reduces hotspots, and ensures uniform heat distribution compared to single-layer designs. An optimal MWCNT: TiO2 ratio of 1.5:0.5 achieves the highest Nusselt number and performance factor, leveraging the thermal conductivity of MWCNT and the wettability of TiO2. Geometric parameters such as wavelength and amplitude further influence performance, with larger wavelengths and moderate amplitudes striking a balance between heat transfer and frictional losses. This work establishes double-layer wavy micro-channels with MWCNT-TiO2 hybrid nanofluids as a promising solution for advanced thermal management applications.