EVOLUTION OF THE CAST INTERNALLY COOLED GAS TURBINE AIRFOIL

Preformed soluble ceramic cores are used in investment castings to provide monolithic cast airfoils having a hollow internal geometry which permits the maximum heat transfer for air cooling. The castings have superior endurance life, greater reproducibility than a fabricated airfoil, and can be manufactured economically.

This paper is a description of the development of cast hollow turbine airfoils with various internal configurations which have been tested on full-scale engines. The limited testing confirms that the product will provide the designer with unlimited latitude and control of the heat transfer characteristics in turbine airfoil applications.

Metallurgical investigation has shown the castings to be sound, and inspection methods for close quality control are described.