Second law analysis of hybrid nanofluid flow in a microchannel heat sink integrated with ribs and secondary channels for utilization in miniature thermal devices

•Second law features of hybrid nanofluid in a microchannel heat sink are assessed.•The heat sink is fitted with the secondary channels and rectangular ribs.•Heat transfer has higher contribution to entropy generation compared with friction.•The lowest thermal entropy generation happens at the front of the ribs.•The Bejan number has smaller magnitudes at higher concentrations.