Influence of Novel Ogive Shape Ribs and Cavities on Local Flow Dynamics and Thermal Characteristics of Microchannel Heat Sink

This study proposes using novel ogive-shaped ribs and cavities to enhance the thermal performance of a microchannel heat sink (MCHS). A three-dimensional conjugate numerical model was employed to investigate the impact of these modifications, i.e., ogive shape ribs and cavities, on the hydro-thermal performance of MCHS in laminar flow regime (Reynolds number 100-1000). The results show that flow separation occurs on the trailing edge of ogive ribs, promoting convective heat transfer by disrupting the boundary layer and enhancing fluid mixing on the downside of ogive ribs due to the formation of recirculation zones. Conversely, stagnant zones are created inside the ogive cavity due to very low fluid local velocity which results in a decrease of local Nusselt number. The study reports a 41.34% maximum improvement in Nusselt number for MCHS with ogive ribs on side channel walls and a maximum thermal enhancement factor of 1.42 for MCHS with ogive ribs on the bottom channel wall.