Measurements of heat transfer coefficient and film cooling effectiveness distribution on a vane using transient liquid crystal technique

The Heat transfer coefficient and the film cooling effectiveness were measured on a turbine NGV airfoil employing the transient liquid crystal technique. There are five rows of compound angle cylinder film holes on the showerhead, 10 rows of cylinder holes on the pressure side, two rows of cylinder holes and two rows of fan-shaped holes on the suction side. All the film cooling gas are supplied by two plenums. The measurements were conducted for a three-vane linear cascade at an inlet Reynolds number of 1.1×10⁵, a mass flow ratio of 5.87% in the first plenum and 1.06% in the second plenum. Detailed distributions of the heat transfer coefficient and the film cooling effectiveness were obtained. The result shows that the heat transfer coefficient and the film cooling effectiveness are higher in the near hole region, and the fan-shaped hole displays higher film cooling effectiveness than the cylinder hole. The film cover region shrinks on the suction side and expands on the pressure side by the influence of passage vortex. In addition, the heat transfer distribution on the suction side is influenced by the flow separation and the passage vortex.