Film cooling of a contoured endwall nozzle vane through fan-shaped holes

• Published in: The International journal of heat and fluid flow 2010-08, Vol.31 (4), p.576-585
• Main Authors: Barigozzi, Giovanna, Franchini, Giuseppe, Perdichizzi, Antonio, Ravelli, Silvia
• Format: Article
• Language: English
• Subjects: Adiabatic effectiveness; Applied sciences; Cascades; Contouring; Coolants; Curvature; Endwall contouring; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Film cooling; Nozzles; Secondary flows; Thermal protection; Vanes
• ISSN: 0142-727X; 1879-2278
• DOI: 10.1016/j.ijheatfluidflow.2010.04.001

The present paper shows the results of an experimental investigation into a nozzle vane cascade with endwall contouring and film cooling. In a film cooled endwall the front area, especially close to the leading edge, is one of the most critical regions to be cooled; in case of a contoured endwall the thermal protection becomes even more difficult because of the endwall curvature effect. Two film cooling hole geometries with four rows of holes were tested: cylindrical holes and conical expanded holes. Tests were performed at low speed ( M 2 is = 0.2) and low inlet turbulence intensity level, with coolant to main stream mass flow ratio varied within the 0.5–2.5% range. Aerodynamic and thermal performances were evaluated in every injection condition. Compared to cylindrical holes, results showed that shaped film cooling holes generate slightly higher secondary losses and provide a better thermal coverage, at the expense of a higher coolant flow injection.