Abstract: A new method for providing stepped radial cooling channels for use in investment casting process, particularly for producing gas turbine blades or vanes, is disclosed. The process involves selecting the cores with two different diameters, smaller diameter cores for airfoil channels and larger diameter cores for root channels. The airfoil cores are bended via especial fixture due to angular design of airfoil relative to root of blade. Then the airfoil cores are inserted into the root cores whereas bended segment of airfoil cores are completely located and locked into the root cores without any requirement to glue or cement at their junction or welding the junction. Then the pairs of cores are placed in the injection wax mold having a cavity with a shape complementary to the final casting design and plurality of grooves therein. Each groove of the mold has a depth equal to a radius of certain number of ceramic cores which correspond to cooling channels of casting.

Abstract: A method for making internal passages for use in investment casting processes, especially for gas turbine components such as blades or vanes. The apparatus includes a first mold cavity having grooves formed therein, a second mold cavity having a shape complementary to the final casting design and ceramic cores. Each groove of the first mold cavity has a depth equal to a radius of a certain number of ceramic cores which correspond to cooling channels. The ceramic cores are placed in the first mold cavity and fugitive wax is injected for temporary positioning of the cores. Two fugitive wax segments are formed about the cores. The fugitive segments locate the ceramic cores in the second mold cavity, and wax is injected about the cores and locating segments to form a pattern for investment casting process.

Abstract: The present invention provides a method for making internal passages for use in investment casting processes, especially for gas turbine components such as blades or vanes. The apparatus comprises a first mold cavity having grooves formed therein, a second mold cavity having a shape complementary to the final casting design and ceramic cores. Each groove of the first mold cavity has a depth equal to a radius of certain number of ceramic cores which correspond to cooling channels. The ceramic cores are placed in the first mold cavity and fugitive wax is injected for temporary positioning of the cores. Two fugitive wax segments are formed about the cores. The fugitive segments locate the ceramic cores in the second mold cavity, and wax is injected about the cores and locating segments to form a pattern for investment casting process.

Abstract: A new, more economical design for intentionally frequency mistuned turbine blades for more efficient turbine engines is disclosed. A rotating disk of a turbine engine includes first turbine blades that alternate between second turbine blades. The second turbine blades are thicker than the first turbine blades, within manufacturing tolerances, in sections from about their mean line to their airfoil tip. The first and second turbine blades can be cast using two different molds, resulting in an economical manufacturing method. As such, the natural frequency of the second turbine blades is about 3% less than the natural frequency of the first turbine blades. As a result of the intentional difference in natural frequencies of the two different turbine blades, the rotating disk does not experience flutter instability.

Abstract: A new, more economical design for intentionally frequency mistuned turbine blades for more efficient turbine engines is disclosed. A rotating disk of a turbine engine includes first turbine blades that alternate between second turbine blades. The second turbine blades are thicker than the first turbine blades, within manufacturing tolerances, in sections from about their mean line to their airfoil tip. The first and second turbine blades can be cast using two different molds, resulting in an economical manufacturing method. As such, the natural frequency of the second turbine blades is about 3% less than the natural frequency of the first turbine blades. As a result of the intentional difference in natural frequencies of the two different turbine blades, the rotating disk does not experience flutter instability.