College of Power and Energy Engineering, Harbin Engineering University, Harbin, Heilongjiang Province, 150001, China
DIME – Department of Mechanical, Energy, Management and Transportation Engineering, University of Genoa, Via Montallegro 1, 16145 Genova, Italy
The cooling efficiency of blade is growing demand with increasing turbine inlet temperature in gas turbine development. Ribs used in cooling channels is a common cooling structure, therefore, many configurations were studied by previous literatures, including angle, spacing, shape etc. However, there are less research about the dislocation ribs structure. In this paper, the 45-deg parallel ribs, crossed ribs and dislocation ribs were investigated by numerical simulation, in order to reveal the heat transfer performance and flow mechanism. Refer to the experiment, SST k-ω model was applied in steady simulation, at Re from 20000 to 50000. Due to the angled ribs can induce the secondary flow and generate small helical vortices at front corner, heat transfer performance was elevated. The large rotating vortices influenced by the ribs arrangement occupy the center channel, thence the dislocation caused different flow and heat transfer results. The results shown that parallel rib has higher heat transfer enhancement than crossed ribs, but pressure loss possess considerable level. At Re=21587, the averaged turbulent kinetic energy of Case2.2 with dislocation ribs is 22.4% lower than parallel ribs. The all 45-deg crossed ribs present higher level of overall thermal performance, and Case2.2 is optimal for the range of Re investigated.