Abstract An improved method of making an air-cooled turbine blade includes the steps of casting a root or dovetail portion and an airfoil section which includes a leading edge, a hollow body portion, and a trailing edge having a plurality of coolant holes formed therein to the minimum practical cast opening size. The blade is then positioned in a fixture which provides a sealed, pressurized chamber around the root portion thereof; and the trailing edge of the blade is deformed to decrease the size of the trailing edge holes. The deformation is limited to the wall cross ties between each pair of holes, and the deformation is stopped when a desired trailing edge coolant efflux is achieved. A blade is thus provided which has wall cross ties which are both thinner and wider than achievable with present state-of-the-art investment casting techniques. Apparatus for performing the trailing edge crimping is also disclosed.
In a method for making an air-cooled turbomachinery blade comprising the steps of: forming into a final shape an airfoil having at least one hollow internal cavity and having a trailing edge with a plurality of openings therein for the efflux of air from the internal cavity, and crimping only the trailing edge portion of the airfoil to a thickness at which a desired amount of air is flowing through said openings.
Claim 2
Dependent Claim
72 words
In a method for making an air-cooled turbomachinery blade comprising the steps of: forming into a final shape an airfoil having at least one hollow internal cavity and having a trailing edge with a plurality of openings therein for the efflux of air from the internal cavity, and crimping only the trailing edge portion of the airfoil to a thickness at which a desired amount of air is flowing through said openings.
Claim 3
Dependent Claim
43 words
In the method of claim 1, the further steps of: supplying pressurized air to the internal cavity at the same time the deforming step is occurring, measuriNg the efflux through said openings, and stopping the deformation when the airflow reaches a predetermined level.
Claim 4
Dependent Claim
38 words
The method of claim 2 wherein the efflux is measured by providing a sealed cavity around a root portion of the blade in fluid flow communication with said internal cavity, and measuring the pressure in said selaed cavity.
Claim 5
Dependent Claim
26 words
The method recited in claim 3 comprising the additional step of: sealing all cooling exhaust passages associated with said blade other than the trailing edge openings.
Claim 6
Dependent Claim
29 words
The method recited in claim 4 comprising the additional step of: providing an enlarged cavity surrounding the trailing edge openings whereby said openings exhaust to a known ambient pressure.
Claim 7
Dependent Claim
25 words
The method recited in claim 2 including the further step of: inspecting individual trailing edge openings to determine that flow will occur through each opening.
Claim 8
Dependent Claim
54 words
In the method of claim 1 wherein said trailing edge comprises a first wall thickness and a second wall thickness separated by a plurality of wall cross ties, the additional step of: stopping the deformation at a point prior to the time when either said first or second wall thickness would start to deform.
Claim 9
Dependent Claim
29 words
The method recited in claim 1 including the further steps of: measuring the trailing edge thickness while deforming same, and stopping the deformation at a desired trailing edge thickness.