Construction of static structures for gas turbine engines

Abstract

Porous or foam metal is utilized in certain static gas turbine engine components that includes the main body of the metal and a coating such as TBC or ceramics. Because of the porosity of the metal the coating bonds to the interstices and hence, eliminates peeling. The outer air seal for the turbine and the vanes of the stator vane assembly are examples of components constructed in accordance with this invention. Cooling is obtained by providing inlet cooling holes into the porous material and exit cooling holes in the coating so as to cool the component and apply a surface of cooling air adjacent to the exterior surface of the coating.

Description

FEDERALLY SPONSORED RESEARCH [0001] None TECHNICAL FIELD [0002] This invention relates to static structures in gas turbine engines and more particularly to these structure that are fabricated from foam metal material and judiciously coated. BACKGROUND OF THE INVENTION [0003] As is well known in the power plant technology, one of the more insidious problems associated with gas turbine engines and particularly those powering aircraft is the structural damage such as cracking of the components that operate in these hostile environments. Needless to say, because of the enormous costs in original and replacement components like vanes and seals, there is a tremendous need in the industry to provide a suitable material that minimizes the repair technique that will not only serve to repair the damaged component, but also to add life to these components and improve performance. [0004] The turbine power plant typically consists of an air inlet, a fan / compressor section, a diffuser, a combusto...

AI Technical Summary

Benefits of technology

[0008] An object of this invention is to fabricate static power plant components from a foam metal, coat the same with a thermal barrier or ceramic coating and include air inlet or exit openings to cool

Problems solved by technology

As is well known in the power plant technology, one of the more insidious problems associated with gas turbine engines and particularly those powering aircraft is the structural damage such as cracking of the components that operate in these hostile environments.

Hence, not only is the engine subjected to extreme temperatures and high stress levels, it is also subjected to foreign matter that is ingested in the inlet of the engine.

In heretofore known materials being utilized in current day engines, a crack or crevice developed in a component tends to propagate and if not attended to within a given time period, this part can lead to a failure of the part and ultimately to an engine failure.

Another concern is that the coating of engine components during the normal operation of the engine has a tendency to degrade or peel off.

The oxides can combine to form particularly deleterious calcium-magnesium-aluminum-silicon oxide systems.

These contaminates can be in a molten state and can infiltrate pores and openings in engine parts that can lead to crack formation and part failure.

Hence, the combined fight between the thermal loads and the stress in addition to the bond strength acerbate the problem so that the coating tends to peel rather than remain local.

This limits the effective thickness that the TBC can be used which, in turn, sets the cooling requirement and engine performance.

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