Effect of leading edge diameter ratio and mainstream Reynolds number on film cooling performance of rotating blade leading edge

The film cooling performance on the leading edge of rotating blade with various leading edge diameter ratio and mainstream Reynolds number was investigated experimentally on a one-stage turbine facility. The film cooling performance was measured by pressure sensitive paint and phase-locked techniques. The numerical simulation was also employed for better understanding the flow filed. Three test model with varied leading edge diameter ratios were studied at three mainstream inlet Reynolds numbers ranged from 8.3 × 10⁴ to 16.6 × 10⁴, and five blowing ratios ranged from 0.5 to 2.0. The variations of span-wise injection angle of film hole (β = 30° and 60°) and density ratio (DR = 1.5 and 1.0) were also performed. The results indicate that higher mainstream Reynolds number and larger leading edge diameter are beneficial for the film coverage at the same condition. And the influence of leading edge diameter is more significant, especially at large blowing ratio. Moreover, the increments of film cooling effectiveness caused by the Reynold number and leading edge diameter are quite different in different leading edge regions. The analyses indicate that the pressure distribution around leading edge and the centrifugal force caused by curved surface, which are varied with the inlet Reynolds number and diameter, determine the film cooling performance in suction side and pressure side of leading edge.