Effect of cylindrical ribs arrangement in the cavity region of the microchannel heatsink with a fan-shaped cavity

Fan-shaped cavity microchannel heatsink with the combination of ribs is an effective configuration to dissipate large amounts of heat at the expense of lower pressure drop. However, the most effective location of circular ribs within a fan-shaped cavity which enhances the performance of a microchannel heat sink is still unknown. In this work, seven different structural units based on the ribs location in the cavity region such as ribs at the front of the cavities (RFC), at the back (RBC), at the centre (RCC), at the front and back (RFBC), at the left (RLC), at the right (RRC) and at the left and right (RLRC) are analysed for the range of Reynolds number from 100 to 500 and the results are compared with the microchannel with fan-shaped cavity only (MHFC) and plain rectangular microchannel heat sink on the basis of Nusselt number, interface temperature, pressure drop and performance factor. A notable finding of this study is identifying a rib as a disruption leading to the splitting of flow into two streams towards the arcuate region of the cavity and results in the enhanced mixing of the mainstream flow and the trapped fluid in the arcuate region. The maximum Nusselt number is exhibited by the RFBC with an increment of about 19% relative to the conventional centre location of the ribs in the cavity (RCC). At a lower Reynolds number, the Nusselt number of RLRC is lower than RCC and RBC however at Re > 300, the Nusselt number of RLRC is nearly equal to RCC whereas the minimum Nusselt number is associated with RRC and RLC among the microchannels having cavities and ribs. Along with the highest Nusselt number the largest value of pressure drop is also associated with RFBC whereas minimum pressure drop is accompanied by RRC and RLC.