Method of Making a Combustion Turbine Component Having a Plurality of Surface Cooling Features and Associated Components

Abstract

A method of making a combustion turbine component includes forming a metallic body by direct metal fabrication (DMF) to have at least one surface portion defining a first plurality of surface cooling features each having a first dimension and at least one second surface cooling feature on at least one of the first plurality of surface cooling features and having a second dimension less than said first dimension and less than 200 μm. Forming the metallic body by DMF may include forming a plurality of metallic combustion turbine subcomponent greenbodies by DMF and assembling the plurality of metallic combustion turbine subcomponent greenbodies together to form a metallic greenbody assembly. The metallic greenbody assembly may be sintered to thereby form the metallic body.

Description

GOVERNMENT CONTRACT[0001]The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of contract No. DE-FC26-05NT42644 awarded by the Department of Energy.FIELD OF THE INVENTION[0002]The present invention relates to the field of metallurgy, and, more particularly, to combustion turbine components having surface cooling features and associated methods.BACKGROUND OF THE INVENTION[0003]A combustion turbine typically includes, in a serial flow relationship, a compressor section to compress the entering airflow, a combustion section in which a mixture of fuel and the compressed air is burned to generate a propulsive gas flow, and a turbine section that is rotated by the propulsive gas flow. After passing through the turbine section, the propulsive gas flow exits the engine through a diffuser section. In ground based combustion turbines used for electricity...

AI Technical Summary

Benefits of technology

[0016]This and other objects, features, and advantages in accordance with the present invention are provided by a method of making a combustion turbine component comprising forming a metallic combustion turbine component body by direct metal fabrication (DMF). The metallic combustion turbine component body may be formed to have at least one surface portion defining a plurality of coarse surface cooling features each having a first dimension, and at least one fine surface cooling feature on at least one of the plurality of coarse surface cooling features and having a second dimension less than the first dimension and less than 200 μm. The cooling features increase the surface area of the combustion turbine component and thereby enhance its ability to transfer heat away from itself, improving high temperature performance.

[0017]DMF advantageously allows for a greater variety of shapes to be formed than casting or forging. In addition, DMF allows the formation of smaller surface features than may be possible with conventional casting or forging processes.

Problems solved by technology

There may, however, be limitations on the size of the combustion turbine components that may be formed by casting.

Likewise, there may be limitations on the size of surface features of the combustion turbine components that may be formed (e.g. it may not be possible to form surface features having dimensions below a certain size).

However, due to the fine grain structure, a forged combustion turbine component generally exhibits relatively low resistance to creep and may thus be unsuitable for use in certain applications Subsequent heat treatment can promote grain growth, however, and it is may be easier to control grain size in a forging than a casting.

In addition, the formation of small surface features on such a combustion turbine component during the forging process may be difficult.

Since forgings are generally solid shapes and cooling passages are later machined into the forging, it may be difficult to machine fine scale internal features on an internal surface of a cooling passage of a forging.

As discussed above, due to process limitations and cost concerns, forming an entire combustion turbine component of a desired shape and having desired surface features by the above processes may be difficult or costly.

However, some features may not be easily or cost effectively formed by casting or forging processes.

In addition, some combustion turbine subcomponents may be constructed from materials that are not easily friction stir welded.

However, a braze joint may be undesirable in some situations and may not provide as strong a bond as desired.

However, a combustion turbine component formed by casting and having an increased surface area may not be desirable in some applications.

Furthermore, certain arrangements of surface cooling features may not be easily formed by casting techniques.

However, recessed grooves may not provide the desired cooling capabilities in some applications.

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