Duct and gas turbine

A duct that forms a passage through which a fluid flows,

• a cross-section of the passage perpendicular to a flow direction of the fluid having a rectangular shape,
• wherein the duct comprises:
• a C-shaped first block forming a part of the rectangular shape;
• and
• a C-shaped second block forming a part of the rectangular shape and disposed opposite the first block across a plane including a central axis of the duct,
• wherein the first block, when viewed along the central axis, includes:
• a first wall portion extending in a first direction perpendicular to an extending direction of the central axis;
• a second wall portion extending from an end portion of the first wall portion on one side in the first direction to one side in a second direction that is perpendicular to the extending direction of the central axis and intersects the first direction;
• and
• a third wall portion extending from an end portion of the first wall portion on the other side in the first direction to the one side in the second direction,
• wherein the second block, when viewed along the central axis, includes:
• a fourth wall portion extending in the first direction;
• a fifth wall portion extending from an end portion of the fourth wall portion on the one side in the first direction to the other side in the second direction;
• and
• a sixth wall portion extending from an end portion of the fourth wall portion on the other side in the first direction to the other side in the second direction,
• wherein the duct comprises:
• a seventh wall portion connecting an end portion of the second wall portion on the one side in the second direction and an end portion of the fifth wall portion on the other side in the second direction;
• and
• an eighth wall portion connecting an end portion of the third wall portion on the one side in the second direction and an end portion of the sixth wall portion on the other side in the second direction,
• wherein a distance between the first wall portion and the fourth wall portion gradually increases from one side toward the other side in the flow direction,
• wherein a plurality of the first blocks are arranged side-by-side in the flow direction, and
• wherein a plurality of the second blocks are arranged side-by-side in the flow direction.