Stator blade and gas turbine provided with same

A stator blade included in a gas turbine, comprising:

• a blade body having a blade shape in a cross section and extending in a blade height direction having a direction component perpendicular to the cross section, the blade body having a blade height extending in a blade height direction from a blade height first side to a blade height second side;
• an outer shroud on the blade height first side of the blade body, and configured to be attached to a turbine casing;
• a plurality of blade air passages extending in the blade height direction inside the blade body;
• and
• a plurality of rear end air passages aligned along the blade height direction,
• wherein the blade body has a leading edge and a trailing edge which each extend in the blade height direction,
• wherein the plurality of blade air passages are aligned from a side of the leading edge toward a side of the trailing edge,
• wherein a front blade air passage on a side closest to the leading edge in the plurality of blade air passages has an inlet opening into which cooling air is to flow, the inlet opening being located in an end of the blade height first side of the front blade air passage,
• wherein the blade air passages adjacent to each other in the plurality of blade air passages communicate with each other in one of a first end of the blade height first side and a second end of the blade height second side to form a serpentine passage meandering in the blade height direction,
• wherein each of the plurality of rear end air passages has a trailing edge opening, and extends toward the trailing edge from a rear blade air passage closest to the trailing edge among the plurality of blade air passages, the trailing edge opening being open in the trailing edge,
• wherein a region of the trailing edge including the end of the blade height first side and not including the end of the blade height second side and extending in the blade height direction is defined as a first side region, a region of the trailing edge separated from the first side region and extending to the blade height second side and including the end of the blade height second side is defined as a second side region, and an opening area of the trailing edge openings of the plurality of rear end air passages per unit length of the trailing edge in the blade height direction is defined as an opening ratio, the opening ratio of the second side region being 0,
• wherein the opening ratio of the trailing edge openings of the plurality of rear end air passages in the first side region is greater than the opening ratio of the trailing edge openings of the plurality of rear end air passages in the second side region, and
• wherein the opening ratio of the trailing edge openings of the plurality of rear end air passages in an intermediate region between the first side region and the second side region in the blade height direction is greater than the opening ratio of the trailing edge openings of the plurality of rear end air passages in the second side region, and the opening ratio of the trailing edge openings of the plurality of rear end air passages in the intermediate region is less than the opening ratio of the trailing edge openings of the plurality of rear end air passages in the first side region.