Numerical study on flow and heat transfer performance of rectangular heat sink with compound heat transfer enhancement structures

Modern gas turbine blade is operating at high temperature which requires abundant cooling. Considering both heat transfer rate and pumping power for internal passages, developing efficient cooling passages is of great importance. Ribbed channel has been proved as effective heat transfer enhancement technology for considerable heat transfer characteristics; however, the pressure loss is impressive. Dimple and protrusion are frequently considered as new heat transfer augmentation tools for their low friction loss in recent years. Numerical simulations are adopted to investigate the thermal performance of rectangular channel with compound heat transfer enhancement structures with ribs, dimples, and protrusions. Among all configurations, the nondimensional dimple/protrusion depths are 0.2. The results present the flow structures of all channel configurations. The Nu/Nu0 distributions of channel section are discussed for each case. The pressure penalty f/f0 and the thermal performance TP are also considered as important parameters for heat transfer enhancement. It can be concluded that the optimal structure of the compound heat transfer enhancement structure is rib + protrusion (D=6 mm) + dimple (D=15 mm).