A flow path structure includes a wall surface in which a flow path is formed, a structure configured to extend in a direction intersecting a main stream direction of a fluid flowing through the flow path from the wall surface, and a concave section forming region formed throughout a range including the structure in the main stream direction and having a concave section formed in the wall surface. As the structure occupies a partial range of the flow path in the flow path cross section intersecting the main stream, a cross-sectional area of the flow path is varied in accordance with positional variation in the main stream direction.

A nozzle vane for a variable geometry turbocharger satisfies 0.45<(Xp/L)≤0.60, where L is a chord length of the nozzle vane, and Xp is a distance between a leading edge of the nozzle vane and a rotation center of the nozzle vane.

The film cooling structure includes a wall part and a cooling hole inclined such that an outlet is positioned rearward of an inlet. The cooling hole includes a straight-tube part and a diffuser part. The diffuser part includes a flat surface, a curved surface curved rearward and forming, together with the flat surface, a semicircular or semi-elliptical channel cross section larger than that of the straight-tube part, a first section and a second section extending from the first section toward the outlet. In the first section, an area of the channel cross section increases as it approaches the outlet. In the second section, the area of the channel cross section increases as it approaches the outlet at an increase rate smaller than that of the first section or is constant. The diffuser part has a width equal to or twice greater than the depth of the diffuser part.

A recuperator disposed in the exhaust duct of a gas turbine engine includes a plurality of recuperator plates arranged in a spaced-apart relationship to define therebetween a plurality of interstices and fluid channels, the plurality of interstices adapted to direct therethrough at least one first stream received at a leading plate edge of the recuperator plates and the plurality of fluid channels adapted to direct therethrough at least one second stream to effect heat exchange between the at least one first stream and the at least one second stream. Each recuperator plate includes, formed at the leading plate edge thereof, a first concavity extending along the leading edge in a direction substantially parallel to a longitudinal axis of the plate. The first concavity extends transversely to a direction of the at least one first stream flowing over each recuperator plate.

An intermediate element is for a blade/rotor disk connection in a rotor of a fluid flow machine. The intermediate element is adapted to a shape of a blade root of a blade and to a blade root slot in a rotor disk for receiving the blade root such that, when arranged between the blade root and rotor disk, the intermediate element prevents contact between the blade root and rotor disk. The intermediate element has, on an outer surface that faces the rotor disk, at least one protrusion to reduce an air flow parallel to an axis of rotation of the rotor between the rotor disk and the intermediate element; and on an inner surface that faces the blade root, a recess that corresponds to the at least one protrusion.

A turbine stage includes a row of airfoils joined to corresponding platforms to define flow passages therebetween. Each airfoil includes opposite pressure and suction sides and extends in chord between opposite leading and trailing edges. Each platform has a contoured flow surface including a purge valley, an elevated bulge and a bowl. The purge valley has a maximum depth at an elevation equal to or greater than a nominal axisymmetric platform surface of the corresponding platform. The purge valley extending tangentially against a purge cavity wall and into the blend area and extending axially from proximate the leading edge of a first airfoil toward the suction side of the first airfoil, and toward the leading edge of a second adjacent airfoil to channel a purge flow. The elevated bulge adjoins the pressure side aft of the leading edge and the bowl adjoins the suction side aft of the leading edge.

The present disclosure provides a fir tree coupling for gas turbine engine parts comprising a load beam having a longitudinal axis, a rounded base, a first side, and a second side, wherein the rounded base has a radius of curvature from the first side to the second side, a tooth running parallel to the longitudinal axis and disposed on the first side of the load beam. The fir tree coupling may comprise a channel through the rounded base across a portion of the radius of curvature from the first side to the second side. The channel may comprise a sidewall having a sidewall step cut into a portion of the channel sidewall.

A housing section of a turbine engine compressor stage or a turbine engine turbine stage that, in particular, has a closed and annular-shaped, radially outer casing. The radially outer casing has radially inwardly extending webs that are angled at a slant relative to the radius.

A turbine blade that includes an airfoil defined by a concave shaped pressure side outer wall and a convex shaped suction side outer wall that connect along leading and trailing edges and, therebetween, form a radially extending chamber for receiving the flow of a coolant. The turbine blade may further include a rib configuration that partitions the chamber into radially extending flow passages, and a blade outer shell that defines an outer surface of the airfoil. The rib configuration is a non-integral component to the blade outer shell.

A turbine arrangement is provided, particularly a gas turbine arrangement, having at least one rotor blade and a turbine disc, the rotor blade having a root portion, the turbine disc having at least one slot in which the root portion of the rotor blade is secured. The slot has a plurality of opposite pairs of slot lobes and a plurality of opposite pairs of slot fillets, and a slot bottom of the slot. The slot bottom is arranged to have a first convex surface section. Furthermore the root portion of the rotor blade has a root bottom with a first concave surface section corresponding to the first convex surface section of the slot bottom. Additionally, the first convex surface section is pierced by an outlet of a cooling duct through the turbine disc.