Improved Turbine Vane Endwall Film Cooling by Using Sand-Dune-Inspired Design

As continuous of the previous sand-dune-inspired design, the Barchan-Dune-Shaped Injection Compound(BDSIC)’s film cooling performance at the endwall region was further investigated both experimentally and numerically. While the public 777-shaped hole was served as a baseline, the BDSIC’s endwall effectiveness was assessed at various blowing ratios. Experiments were performed in a single-passage transonic wind tunnel using pressure-sensitive paint(PSP) technique. Carbon dioxide was used as coolant with density ratio of DR=1.53. The purge slot’s blowing ratio was fixed at M=0.3, but the coolant holes were adjusted within M= 0.5–2.0. The measured experimental results indicate that the film distribution at the endwall is strongly affected by the passage flow structures. The BDSIC holes demonstrate much higher film effectiveness than the 777-shaped holes for all blowing ratios, ～30% enhancement for regionally averaged effectiveness at M=1.0 and ～26% at M=2.0. As shown by the numerical results, the existence of BDSIC reduced the coolant penetration effect at a higher blowing ratio. Coolant was deflected and its momentum increased in the streamwise direction, therefore providing more robust film coverage over the endwall region. The anti-counter-rotating vortex pair induced by the BDSIC further stabilized the coolant film and increased the coolant spreading downstream.