Numerical study of flow characteristics in rotating S-shaped passage with ribs

For better understanding of the flow characteristics of turbine blade internal cooling passage, a numerical study was conducted to investigate the influences of rib, turn and rotation on the flow characteristics in full S-shaped passage with ribs. The Reynolds number was 17 000, three outlet discharge ratios were 27%, 49%, 24%, rotation numbers were 0, 0.03, 0.06, 0.09. The results reveal that the fluid has stronger turbulence and lower velocity with higher blockage ratio near the leading edge of passage 1. Turn causes the flow separation and shift of mainstream downstream the turn. There is a big range of low velocity area near the bulkhead in the passage 3. Coriolis force makes the fluid shift towards the wall to which the Coriolis force points, the mainstream shifts towards suction surface and pressure surface in passage 2 and passage 3 respectively. Rotation affects the distribution of the secondary flow in passage and promotes the flow of low velocity circumfluence area downstream the turn.