Air-cooled turbine blade

Abstract

An air-cooled gas turbine blade providing improved cooling characteristics is disclosed. The turbine blade includes several internal passages for conveying cooling air therethrough during turbine operation to provide the desired cooling effect. Two distinct passages are provided to cool the airfoil leading and trailing edges, respectively. Two serpentine cooling passages are disposed so as to efficiently cool each side of the airfoil. Disposed in the middle of the airfoil is an additional, distinct passage. The platform is cooled by three serpentine cooling passages. Two of these passages are in outlet fluid communication with the inlet to the middle airfoil passage. As cooling air traverses these two passages, heat is transferred, from the base simultaneously cooling it and warming the air. This warmed air is next directed through the middle airfoil passage, providing a slight warming effect to the center portion of the airfoil. This counteracts the tendency of the side cooling passages to over cool the center of the airfoil. In this way, a more uniform temperature gradient can be achieved throughout the airfoil, as well as the platform, minimizing internal stresses and enhancing blade operating characteristics.