Film cooling structure

Abstract

A film cooling structure 10 includes a structural wall 11 that has an outer surface 12 exposed to combustion gas and an inner surface 13 positioned opposite to the outer surface 12, and film cooling holes 14 are formed at the structural wall 11 and introduce cooling air from the inner surface 13 toward the outer surface 12 in order to perform film cooling. The film cooling hole 14 includes an introducing portion 14a that extends to a middle position in the structural wall 11 from the inner surface 13 toward the outer surface 12, an enlarged portion 14b of which the cross-sectional area is gradually increased toward the outer surface 12 from an end of an outer surface side of the introducing portion 14a and which is opened at the outer surface 12, and a partition portion 16 that partitions the inside of the enlarged portion 14b into a plurality of spaces in a width direction of the hole perpendicular to a flow direction of the combustion gas.

Description

BACKGROUND OF THE INVENTION[0001]1. Technical Field of the Invention[0002]The present invention relates to a film cooling structure that is suitable for film cooling of the surface of a component (turbine blade or the like) of a gas turbine engine.[0003]2. Description of the Related Art[0004]The efficiency of a gas turbine engine is increased as combustion gas temperature rises. However, the combustion gas heats a structural wall of a component (a combustor liner, a turbine blade, a turbine shroud, or the like), that is disposed on a flow passage for combustion gas, to high temperature. Accordingly, in order to efficiently cool the structural wall of such the component, there is employed a film cooling structure. In the cooling structure, a cooling passage is formed therein, convection cooling is performed by making cooling air flow through the cooling passage, and film cooling is performed by making the cooling air be ejected from film cooling holes onto a surface, which is exposed...

AI Technical Summary

Benefits of technology

[0019]The invention has been made in consideration of the above-mentioned problems, and an object of the invention is to provide a film cooling structure that can increase an enlarged angle of an enlarged portion and improve average film cooling efficiency.

[0022]Since the film cooling hole includes the partition portion that has been formed as described above, an effective area expansion ratio may be reduced. Accordingly, even though the enlarged angle of the enlarged portion in a transverse direction is large, the separation of the cooling air is suppressed. Therefore, since it is possible to effectively diffuse cooling air as compared to the related art, the enlarged angle of the enlarged portion in the transverse direction can be made large. As a result, it is possible to spread the cooling air thinly and broadly on the outer surface of the structural wall, and to improve average film cooling efficiency. Meanwhile, the definition of the average film cooling efficiency will be described below.

[0023]Further, since it is possible to spread the cooling air thinly and broadly as compared to the related art, the number of film cooling holes formed at the structural wall may be reduced. Accordingly, the number of processes for manufacturing the film cooling structure can be reduced. Furthermore, as the number of film cooling holes is reduced, the amount of cooling air extracted from the compressor of the gas turbine engine can be decreased. Therefore, engine efficiency can be improved.

[0025]As described above, the partition portion does not completely partition the film cooling hole in the transverse direction, and extends over the entire structural wall in a thickness direction. Therefore, it is easy to form the film cooling hole.

[0026]From the above description, according to the invention, it is possible to obtain advantages of increasing an enlarged angle of an enlarged portion and improving average film cooling efficiency.

Problems solved by technology

For this reason, there have been problems that the cooling air 5 is not effectively diffused and it is difficult to improve average film cooling efficiency.

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