Study of film cooling performance for turbine blade trailing edge with different V-shaped rib orientations

To achieve higher cooling performance at trailing edge (TE), a novel ribbed cutback structure is proposed for TE cooling, which has rib structures on the cutback surface for heat transfer enhancement. Numerical simulations have been performed on the effects of V-shaped rib orientation on the film cooling characteristics and flow physics. Three V-shaped rib angles of 30°, 45° and 60° for three blowing ratios are studied. Due to the relatively small rib height, the effect of V-shaped ribs on the cooling effectiveness is not notable. The disadvantage of V-shaped ribs mainly exhibits at the downstream area of cutback surface. With the increase of V-shaped rib angle, the cooling effectiveness becomes lower, but the values are still above 0.9. The V-shaped ribs obviously enhance the heat transfer on TE cutback surface. The area-averaged heat transfer coefficient of the V-rib case is higher than that of the smooth case by 26.3-41.2%. For the same opening orientation, the 45° V-rib case has higher heat transfer intensity than the other two V-shaped rib cases. The heat transfer intensity of the 30° V-rib case is higher in the downstream region than the other two cases, but lower in the upstream region in which the difference becomes smaller with the increase of blowing ratio. The 45° V-rib case and the 60° V-rib case both reach the maximum value of area-averaged heat transfer intensity for blowing ratio is 1.0. For higher blowing ratio, the 30° V-rib case and the 45° V-rib case outperform 2.1% and 6.7% higher value relative to the 60° V-rib case respectively. The heat transfer intensity on the cutback surface is strongly affected by the rib opening orientation. The lower heat transfer coefficient areas of Λ-shaped rib case are in the included angle and near the centerline. While the higher heat transfer areas are mainly distributed on both spanwise sides, the range is less than that of the V-shaped rib case.