Investigation of heat transfer in dimple-protrusion micro-channel heat sinks using copper oxide nano-additives

The ability of controlling the temperature of a system by using heat transfer and thermodynamics-based technology is known as thermal management. Thermal management is a crucial problem which is to be addressed in the various fields. This study accompanies a numerical work to provide a solution for heat transfer enhancement by studying a straight rectangular cross-section channel. The selected channel is used with and without disturbance in the form of dimple-protrusion with circular & through geometry. Water is employed as the base fluid for identifying flow behavior and heat carrying capacity while the heat flux is applied as a boundary condition. Furthermore, using the same boundary condition, copper oxide nanoparticles with the concentration of 0.10%, 0.15% and 0.20% respectively are added in the channels. Flow conditions are varied from 100 to 900 considering the laminar regime with fully developed flow . Performance enhancement criteria are evaluated by considering the Nusselt number , friction factor , and base cooling. The fully developed velocity profile is maintained at the inlet of test section for all Reynolds numbers . Semi-Implicit Method for Pressure Linked Equations (SIMPLE) pressure-velocity coupling is used with the second-order upwind scheme for discretization and solution approximation. It is observed that circular dimple-protrusion channel is effective for high Reynolds numbers and through dimple protrusion is efficient for intermediate Reynolds numbers . 10% improvement in Nusselt number is observed for circular dimple-protrusion channel with 0.2% CuO concentration by comparing the results of dimple-protrusion channel with straight channel at same nanoparticle concentration. Compared to straight channel with 0% and 6% particles concentration 5% and 7% increase in Stanton number is observed for through disruption case. Dimple channel on the other hand showed 3% and 5% increase. Furthermore, the formation of vortices at high Reynolds number is observed in circular dimple-protrusion channel.