Investigation of High-Pressure Turbine Endwall Film-Cooling Performance Under Realistic Inlet Conditions

Progress in materials and manufacturing techniques allows an increase of the mean turbine inlet temperature, resulting in improved efficiency and specific power of the turbine. Because of the combustor characteristics, thermal and aerodynamic nonuniformities can be present at the turbine inlet section. Then, a further increase in the inlet temperature might also generate harmful conditions for vane endwalls. In other words, it is necessary to apply realistic turbine inlet temperature and velocity profiles to evaluate these real effects. The objective of the present work is to predict and analyze a cooled high-pressure vane in terms of adiabatic effectiveness and aerodynamic behavior. An endwall cooling geometry with both fan-shaped and cylindrical holes has been investigated. Inlet nonuniformities in total temperature and velocity profile have been considered in order to simulate realistic conditions. Once the inlet total temperature profile is imposed, a considerable increase in the laterally averaged adiabatic cooling effectiveness, generated by the radial total temperature distribution, can he achieved. The inlet swirl limits this gain of cooling efficiency since it modifies the horseshoe vortex development and generates a stronger passage vortex with a detrimental effect for the platform cooling.