Combustion burner, combustor, and gas turbine having a swirl vane with opposite directed surfaces

A combustion burner comprising:

• a nozzle;
• and
• a swirl vane disposed in an axial flow path extending along an axial direction of the nozzle around the nozzle, wherein the swirl vane includes
• a tip portion for swirling gas in a swirl direction, the gas flowing through a radially-outer region of the axial flow path, and
• a root portion disposed on an inner side in a radial direction of the nozzle as seen from the tip portion, the root portion having a cutout on a side of a trailing edge,
• wherein the radially-outer region and a radially-inner region of the axial flow path communicate with each other without being partitioned, at least in a range in the axial direction in which the swirl vane is disposed,
• wherein the swirl vane has a pressure surface, a downstream region of the pressure surface of the root portion being defined by the cutout as a curved surface which curves in a direction opposite to the swirl direction toward the trailing edge,
• wherein the pressure surface of the swirl vane at the tip portion has a curved surface curving in the swirl direction toward the trailing edge,
• wherein the pressure surface of the swirl vane has a stepped portion between the curved surface of the tip portion and the curved surface of the root portion,
• wherein an airfoil of the root portion has a shape same as that of an airfoil of the tip portion in an upstream region, and has a shape such that a portion corresponding to the cutout is cut out from the airfoil of the tip portion in the downstream region, and
• wherein the trailing edge of the root portion of the swirl vane is formed by a downstream edge of the pressure surface of the root portion including the curved surface so as to be disposed on a suction surface of the airfoil of the root portion having the same shape as the tip portion.