Numerical study on performance enhancement of novel wavy double-layered microchannel heat sink: Synergistic effects of pin fins and secondary channels

A three-dimensional numerical investigation is conducted to assess the thermohydraulic performance of a novel wavy double-layered microchannel heat sink incorporating circular pin fins and inclined secondary channels. 28 configurations are examined by varying wave amplitude (0, 138, and 259 μm), wavelength (1.25, 2.5, and 5 mm), and geometric features, using water as coolant and copper as substrate at Reynolds numbers from 200 to 600. Results show that increasing wave amplitude significantly enhances flow velocity and heat transfer, but also increases pressure drop. Conversely, longer wavelengths reduce pressure loss due to fewer wave-induced obstructions. The best thermal performance is achieved for the configuration with 259 μm amplitude and 5 mm wavelength containing only secondary channels, yielding a heat transfer coefficient of 28746.63 W/m 2 .K and a performance evaluation criterion of 4.42 at Reynolds number 600. Additionally, the configuration with both pin fins and secondary channels exhibits the lowest thermal resistance, showing a 69.15% reduction compared to the straight single-layered baseline. Enhanced fluid mixing and temperature uniformity in the proposed designs result in improved thermal effectiveness. The findings demonstrate the positive synergistic role of wavy walls, pin fins, and secondary channels in optimizing microchannel cooling performance for high heat flux applications.