Thermo-hydraulic performance inside convergent rectangle channel with large-deformed dimples

Abstract

The cooling technology of convergent rectangle channel is widely applied in heat exchangers, electronic devices and aerospace, especially in the field of turbine blade internal cooling.A numerical study was conducted to research the thermo-hydraulic performance inside a convergent rectangle channel with large-deformed dimples. The heat transfer and flow characteristics were presented to demonstrate the heat transfer enhancement mechanism. The effect of dimple configuration, dimple depth, and dimple radius on thermo-hydraulic performance were discussed at Reynolds numbers ranging from 15,000 to 65,000. The numerical results revealed that the large-deformed dimple structure disrupts the boundary layer flow, resulting in better mixing between the boundary layer flow and the core fluid. The dimple configuration of diminishing dimples showed better heat transfer performance and lower pressure loss. The Nusselt number ratio, friction factor ratio, and performance evaluation criteria (PEC) increase with rising dimple depth and dimple radius. Within the scope of the present work, the maximum PEC was 1.62 when the dimple configuration was diminishing, the dimple depth was 5mm, and the dimple radius was 10mm.