Patent Grant
7008181
1. Field of the Invention
The invention relates to aircraft gas turbine engine turbine cooling systems and, particularly, to rotating annular cavities that accumulate debris from such systems.
2. Description of Related Art
Gas turbine engines typically include a core engine having in serial, axial flow relationship, a high pressure compressor to compress the airflow entering the core engine, a combustor in which a mixture of fuel and the compressed air is burned to generate a hot gas flow. A high pressure turbine is rotated by the hot gas flow and drives the high pressure compressor through an interconnecting high pressure shaft. A low pressure turbine aft of the high pressure turbine drives a fan forward of the high pressure compressor by a low pressure shaft. Various cooling systems are used to duct relatively cool compressor air to the turbine for cooling purposes. The cooling air for turbine cooling contains a small amount of dust and debris which can accumulate in various annular cavities in the turbine as well as other rotating parts of the engine. As an example, cooling air may be flowed though holes in a shaft of a turbine disk and accumulate in an adjacent annular cavity in a hub of the disk. Such an arrangement may be found in a high pressure turbine of a General Electric CF6-80 series engine.
Such cavities are closed at an outer diameter and open at an inner diameter of the hub. Dust and debris can become entrapped and build up over time with continued operation of the engine. Since the rotor internal airflow usually has both axial and circumferential velocity relative to the rotor, such debris can circumferentially scrub the rotating part internal surfaces and, over time, cause damage to the parts.
It is highly desirable to have an apparatus that can prevent debris from circumferentially scrubbing internal surfaces of rotating part cavities that are closed at an outer diameter and open at an inner diameter of the parts and which over time can cause damage to the parts.
An annular air baffle for use with a cavity of an annular rotatable gas turbine engine part includes an annular split ring supporting a plurality of circumferentially spaced apart fins. The cavity is closed at a radially outer diameter and open at a radially inner diameter of the part. The ring and the fins may be integrally formed in one piece. In the exemplary embodiment of the ring, the fins have common surfaces with the ring. The common surfaces are circular cross-sectional surfaces of the ring and radially outer rounded corners of the fins. The fins have triangular cross-sectional shapes with first, second, and third sides, rounded first radially inner corners between the first and second sides, rounded second radially inner corners between the second and third sides, and the radially outer rounded corners between the first and third sides. The fins extend radially inwardly from the annular split ring. The fins may have other cross-sectional shapes such as circular or the fins may be hemispherical.
The foregoing aspects and other features of the invention are explained in the following description, taken in connection with the accompanying drawings where:
Illustrated in
Referring to
The above exemplifies a general problem that may occur in a rotating or rotatable annular gas turbine engine part having a cavity 50 closed at a radially outer diameter 52 and open and exposed to internal airflow at a radially inner diameter 56 of the part exemplified by the first hub 36. Centrifugal forces tend to extract dust and debris from the internal cooling airflow 54, trapping it in the radially inwardly facing cavity 50. Dust and debris then rotates in the cavity 50 relative to the rotating part causing a scrubbing action which then causes abrasive damage to the disk in a region including the cavity 50. This damage can be severe enough to cause the disk to be unserviceable at overhaul.
An annular air baffle 60 disposed in the annular cavity 50 is used to reduce or prevent this damage. The air baffle 60 reduces or eliminates the differential in circumferential velocity between the cooling flow and the rotating gas turbine engine part, thereby, preventing entrained debris from scrubbing the surface of the rotating part. The air baffle 60 also acts as a physical barrier that prevents entrained debris from scrubbing the surface of the rotating part.
Referring to
The fins 72 illustrated in
The fins 72 and ring 70 may have alternative shapes. The fins 72 may have other cross-sectional shapes such as circular or the fins may be hemispherical. Illustrated in
While there have been described herein what are considered to be preferred and exemplary embodiments of the present invention, other modifications of the invention shall be apparent to those skilled in the art from the teachings herein and, it is therefore, desired to be secured in the appended claims all such modifications as fall within the true spirit and scope of the invention. Accordingly, what is desired to be secured by Letters Patent of the United States is the invention as defined and differentiated in the following claims.
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| Number | Date | Country | |
|---|---|---|---|
| 20050053460 A1 | Mar 2005 | US |
