Thermal–hydraulic performance of transverse ridge geometries in water-cooled microchannel heat sinks

Introduction Liquid-cooled microchannels offer an effective approach to removing high heat loads from compact electronic systems. Although surface modifications can enhance heat transfer, their benefits must be evaluated against the accompanying hydraulic penalties. This study investigates the influence of transverse ridge geometry on the thermal and hydraulic performance of a water‐cooled copper microchannel. Methods Two-dimensional conjugate heat-transfer simulations were performed using COMSOL Multiphysics to compare semicircular, triangular, and rectangular transverse ridges. Ridge height ( e = 0.05–0.15 mm), pitch ( p s = 0.25–0.50 mm), and Reynolds number ( Re = 100–1000) were systematically varied, resulting in 135 ridged‐channel simulations and five smooth-channel reference cases. Thermal and hydraulic performance were evaluated using the Nusselt number, pressure drop, thermal performance factor (TPF), and a Pareto analysis of heat‐transfer enhancement versus reference-width pumping power. Results At Re = 1000, e = 0.15 mm, and p s = 0.40 mm, the smooth channel yielded a Nusselt number of 14.51, compared with 16.83, 17.98, and 23.47 for the semicircular, rectangular, and triangular ridges, respectively. These values correspond to heat-transfer enhancements of 16.0%, 23.9%, and 61.8%. Triangular ridges provided the greatest thermal enhancement but incurred the highest pressure-drop penalty. The maximum TPF of 1.37 was achieved with triangular ridges at Re = 1000, e = 0.15 mm, and p s = 0.50 mm, which also yielded the highest Nusselt number of 24.01. Pareto analysis indicated that rectangular ridges occupied much of the lower‐pumping‐power frontier, while triangular ridges provided superior heat‐transfer enhancement at higher pumping demand. Discussion Ridge geometry, height, and pitch collectively influence microchannel thermal‐hydraulic performance. Triangular ridges are favorable when maximizing heat transfer is the primary objective, whereas rectangular ridges offer competitive performance under tighter pumping-power constraints. These findings highlight the importance of considering hydraulic penalties alongside thermal enhancement when designing ridge‐enhanced microchannel heat sinks.