This numerical research study focuses on impacts of using twisted rib geometry on the hydrothermal performance and entropy generation characteristics of biologically synthesized Ag/water nanofuid fowing in heat sink minichannels. To this end, twelve diferent twisted rib geometries (Case 1 to 12) were designed where the double-row ribs were twisted at the bottom and top portions with twist angles between −45° and +45°. To elucidate the cooling performance comprehensively, four diferent Reynolds numbers (Re=500, 1000, 1500, and 2000) and four diferent nanoparticle concentrations (휑=0%, 0.1%, 0.5%, and 1%) were included in the numerical computations. Results revealed that using twisted ribs signifcantly smoothen the fuid fow and reduces pressure drop remarkably depending on twist angles, nevertheless, it deteriorates the cooling performance. In Case 12, the convective heat transfer coefcient reduces by up to 15.8% at Re=2000 and 휑=1%, compared to the base case. However, pumping power requirement is decreased by 43.9% in this case. Nanoparticle incorporation contributes to enhancement of convective heat transfer coefcient by up to 13.5% at the lowest Re. Frictional entropy generation considerably decreases (up to 31%) when twisted ribs are utilized. However, thermal entropy generation can increase up to 36%, due to inefective cooling with twisted ribs. This work can be regarded as a frst study in the feld concerning the efects of top and bottom twist angles on hydrothermal performance and entropy generation in nanofuid-cooled mini-channel heat sinks
