Thermohydraulic Performance of a Microchannel Heat Sink with Novel Transverse-Section Triangular Ribs: A Parametric Numerical Study

A three-dimensional conjugate heat-transfer model was used to investigate laminar water flow in a silicon microchannel heat sink equipped with novel staggered transverse-section triangular ribs, whose triangular cross-section is defined directly in the channel transverse plane, normal to the mean flow direction. Simulations were performed for 100≤Re≤400 under a uniform base heat flux of 1.0 MW/m2. Rectangular and triangular ribs were first compared at the same frontal-area blockage ratio, BR=25%. The rectangular configuration provided a slightly higher performance-evaluation criterion (PEC) up to Re=200, whereas the triangular configuration became superior at higher Reynolds numbers and yielded an 8.7% higher PEC at Re=400. A sequential parametric study then examined triangular-rib width, height, blockage distribution, and streamwise spacing. At BR=37.5% and Re=400, the full-height/variable-width configuration produced a 55.3% higher Nusselt number and a 30.7% higher PEC than the corresponding full-width/variable-height configuration. Reducing rib spacing from 0.40 to 0.20 mm increased PEC by 74.5%, from 1.37 to 2.40, while the Fanning friction factor increased from 0.118 to 0.279. The complementary heated-base indicators, i.e., overall Nusselt number and PECh, confirmed the main performance trends, supporting the conclusion that rib profile, blockage distribution, and spacing jointly govern the thermohydraulic performance of transverse-section triangular-rib microchannels.