Turbine blade cascade endwall

Abstract

Provided is a turbine blade cascade endwall that is capable of reducing crossflow and is capable of reducing secondary-flow loss that occurs in association with the crossflow, therefore being capable of achieving enhanced turbine performance. A convex portion (11) that is gently swollen as a whole, that has an apex (P1) at a position of 0 to 20% pitch in a position of 5 to 25% Cax, that gently slopes from this apex (P1) toward a downstream side and a suction side surface of an adjacently disposed turbine stationary blade (B1) or turbine moving blade, and that slopes slightly steeply from the apex (P1) toward an upstream side is provided between one turbine stationary blade (B1) or turbine moving blade and another turbine stationary blade (B1) or turbine moving blade disposed adjacent to one turbine stationary blade (B1) or turbine moving blade.

Description

TECHNICAL FIELD[0001]The present invention relates to a turbine blade cascade endwall.BACKGROUND ART[0002]On a turbine blade cascade endwall in a turbine serving as a motive power generator that obtains motive power by converting kinetic energy of a fluid to rotational motion, a so-called “crossflow (secondary flow)” occurs from the pressure side of one turbine blade to the suction side of an adjacent turbine blade.[0003]In order to enhance the turbine performance, it is necessary to reduce this crossflow and to reduce secondary-flow loss that occurs in association with the crossflow.[0004]Therefore, as a turbine blade cascade endwall that reduces such secondary-flow loss associated with crossflow to improve turbine performance, one having non-axisymmetric irregularities formed thereon has been known (for example, see Patent Citation 1).Patent Citation 1: U.S. Pat. No. 6,283,713, Specification.DISCLOSURE OF INVENTION[0005]In a turbine blade cascade endwall disclosed in the above-des...

AI Technical Summary

Benefits of technology

[0007]The present invention has been conceived in light of above-described circumstances, and an object thereof is to provide a turbine blade cascade endwall that is capable of reducing a crossflow and that is also capable of reducing secondary-flow loss that occurs in association with the crossflow, thus being capable of achieving enhanced turbine performance.

[0010]With the turbine blade cascade endwall according to the first aspect of the present invention, because the static pressure near the convex portion can be reduced and the flow of working fluid in the axial direction can be increased, it is possible to reduce the crossflow and to reduce secondary-flow loss that occurs in association with the crossflow; therefore, enhanced turbine performance can be achieved.

[0012]With the turbine blade cascade endwall according to the second aspect of the present invention, because the static pressure near the concave portion can be increased and the flow of working fluid in the axial direction can be increased, it is possible to reduce the crossflow and to reduce secondary-flow loss that occurs in association with the crossflow; therefore, enhanced turbine performance can be achieved.

[0014]According to the turbine blade cascade endwall as described above, because the flow rate of the working fluid passing near the throat increases, thereby reducing the static pressure thereof and alleviating a pressure gradient generated at the suction side surface of the turbine stationary blade or the turbine moving blade in a blade-height direction, vortices generated at the suction side surface of the turbine stationary blade or the turbine moving blade can be suppressed, and therefore, it is possible to reduce secondary-flow loss associated with these vortices.

[0016]With the turbine according the third aspect of the present invention, because it is equipped with a turbine blade cascade endwall that is capable of reducing the crossflow and is capable of reducing secondary-flow loss that occurs in association with the crossflow, it is possible to achieve enhanced overall turbine performance.

[0017]With the present invention, an advantage is afforded in that it is possible to reduce the crossflow and to reduce secondary-flow loss that occurs in association with the crossflow, and therefore, enhanced turbine performance can be achieved.

Problems solved by technology

However, in the convex portion formed on the pressure-side trailing edge, static pressure declines thereat, and a discharge angle of a blade outlet ends up increasing, which deteriorates the performance of a blade cascade located downstream of a blade cascade having irregularities, thereby posing the risk of decreasing the overall performance of a turbine having a plurality of blade cascades.

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