Thermal hydraulic performance augmentation by petal-shaped ribs in a two-pass cooling channel

Abstract

The increase of inlet gas temperature will lead to security problem of turbine blades. Internal cooling channels are usually used to ensure the safe operation temperature of the turbine blades. Rib-roughness can effectively enhance the cooling performance of the internal channels. To further promote the channel performance, a novel petal-shaped rib is proposed and numerically simulated with SST k-ω model in this paper. Three different rib types, including square rib, a-quarter-cylinder rib and petal-shaped rib, are compared under the identical rib height and rib cross-section area. The results showed that the petal-shaped and a-quarter-cylinder ribs have larger heat transfer performance than the normal square rib. The heat transfer of the petal-shaped rib is the largest and increases by up to 21.14% compared with square rib. While the friction factor of the channel with the petal-shaped rib is 10.04% smaller than the square rib. The thermal performance factor of the petal-shaped rib reaches up to 2.02, which concludes a significant increment of 22.91% compared with the square rib. The results prove that the petal-shaped rib has great potential to enhance the thermal performance of the cooling channel and can be applied in the design of cooling channels for gas turbine blades.