Thermo-hydraulic analysis of a novel microchannel with zigzag cavities and waterdrop-shaped ribs for electronic chip cooling

• The zigzag microchannel with waterdrop-shaped ribs (Structure-4) solves contradiction between enhanced heat transfer and increased flow resistance. • Structure-4 optimises flow and heat transfer performance through a unique synergistic effect. • Structure-4 effectively disrupts thermal boundary layers and suppresses flow separation. • Structure-4 reduces thermal resistance by 23.69%, and lowers N s,a by 16.9–22.5% under certain conditions. A novel microchannel integrated with zigzag cavities and waterdrop-shaped ribs was proposed in this study to enhance heat transfer. Numerical simulations were conducted to analyze the thermal–hydraulic performance of water in the novel microchannel, while the entropy generation principle was employed to elucidate the underlying mechanisms. Results show that: within a Reynolds number ( Re ) range of 341–796, compared with the straight microchannel (Structure-1), the zigzag microchannel (Structure-2), the straight microchannel with waterdrop-shaped ribs (Structure-3), the heated-surface average temperatures of the zigzag microchannel with waterdrop-shaped ribs (Structure-4) decreased by 24.1–30.1 K, 18.3–24.2 K, and 1.0–2.5 K, maximum temperature reduced by 33.3–39.7 K, 21.8–27.4 K, and 2.7–3.7 K, while the average Nusselt numbers ( Nu ave ) exhibited maximum increments of 106.01%, 80.21%, 12.15%, respectively. At Re = 568, the pressure drop ( Δp ) of Structure-3 increases nearly seven times compared with Structure-1, and 32.42% higher than Structure-4. Notably, Structure-4 outperforms in both heat transfer and flow resistance. For all the same Re , the entropy generation increase number ( N s,a ) of Structure-4 is 16.9%–22.5% lower than Structure-3, indicating that a synergistic combination of zigzag cavities and waterdrop-shaped ribs is superior in reducing the irreversibility of flow and heat transfer. The flow resistance of Structure-4 was reduced by 50.08%–57.73% compared with Structure-1 in the study range. The results can clarify the differences in heat transfer and fluid flow among diverse structures, and provide a foundation for microchannel selection, optimal design, and heat transfer efficiency enhancement.