Patent ID: 9689272
Date: 2017-06-27
CPC Classifications: F01D

Claim:
1. A gas turbine comprising: a plurality of turbine blades mounted to a rotatable turbine shaft; a plurality of turbine vanes secured so as to be axially opposite with respect to the turbine blades; a plurality of ring segments circumferentially surrounding the turbine blades, respectively; a plurality of outer shrouds circumferentially surrounding the turbine vanes, respectively, the outer shrouds being provided so as to be axially opposite with respect to the ring segments; and a combustion gas flow-path provided in the ring segments and the outer shrouds, for passing combustion gas, wherein a first outer shroud of the plurality of outer shrouds is positioned on an upstream side of a first ring segment of the plurality of ring segments in a gas flow direction of the combustion gas, seal gas having a temperature lower than a temperature of the combustion gas is fed between the first ring segment and the first outer shroud into the combustion gas flow-path, an inner diameter of the first ring segment is larger than that of the first outer shroud, an outer diameter of a turbine blade surrounded by the first ring segment is larger than that of a turbine vane surrounded by the first outer shroud, the first outer shroud has a guide surface that is provided on an inner circumference thereof on a downstream side of the gas flow direction, and the guide surface guides the combustion gas passing therein toward an inner circumferential surface of the first ring segment, the guide surface changes a part of the combustion gas flowing toward the first ring segment, and the guide surface is formed such that a flow passage area of the combustion gas flow-path is gradually increased, the gas turbine has a plurality of areas including: the guide surface is provided in the first area, an intersection point between a tangent of the guide surface and the inner circumferential surface of the first ring segment is positioned on the second area.