An assembly is provided for a turbine engine. This assembly includes a static structure and an impeller rotor housed within the static structure. The impeller rotor includes a vane structure and a shroud. The vane structure includes a first sidewall, a second sidewall and a plurality of vanes arranged circumferentially about a rotational axis. The vanes include a first vane. The first vane includes a first portion, a second portion and a third portion. The first portion is axially between the first sidewall and the second sidewall. The second portion is radially between the first sidewall and the shroud. The third portion is radially between the second sidewall and the shroud. The shroud circumscribes the vane structure. A gap is formed by and extends between the shroud and the static structure. A dimension of the gap changes as the gap extends along the shroud.

A turbine impeller includes: a hub portion coupled to an end of a rotational shaft; a plurality of main blades disposed at intervals on a peripheral surface of the hub portion; and a short blade disposed between two adjacent main blades among the plurality of main blades. An inter-blade flow channel is formed between the two adjacent main blades so that a fluid flows through the inter-blade flow channel from an outer side toward an inner side of the turbine impeller in a radial direction. In a meridional plane, a hub-side end of a leading edge of the short blade is disposed on an inner side, in the radial direction, of a hub-side end of a leading edge of the main blade.

A method for forming a component for a gas turbine engine may include forming a first portion of the component that includes a cast metal or metal alloy, forming a second portion of the component that includes presintered preform defining at least one support structure, positioning the second portion on the first portion to define an assembly such that the first portion and the second portion define at least one cooling channel therebetween, and heating the assembly to join the first portion and the second portion and form the component.

A turbine rotor blade according to at least one embodiment of the present invention is to be connected to a rotational shaft so as to be rotatable around an axis and includes: a hub having a hub surface inclined with respect to the axis in a cross-section along the axis; at least one rotor blade disposed on the hub surface; and a connection passage disposed inside the turbine rotor blade and connecting a first opening disposed in the at least one rotor blade and a second opening disposed downstream of the first opening in the turbine rotor blade.

A radial turbine rotor associated with an engine includes a disk, and a plurality of blades spaced apart about a perimeter of the disk. Each blade includes a forward end, an aft end and a root. The radial turbine rotor includes a plurality of sectors, with each sector coupled to the root of a respective blade of the plurality of blades. Each sector of the plurality of sectors defines a first surface configured to contact a working fluid and a second surface configured to be coupled to the disk, and each sector of the plurality of sectors defines at least one pocket between the first surface and the second surface proximate the forward end that extends toward the aft end. The radial turbine rotor includes a feather seal slot defined between adjacent sectors of the plurality of sectors proximate the first surface.

An impeller of a rotating machine according to at least one embodiment includes: a disc; a cover disposed on an opposite side of a radial passage from the disc in an axial direction; and a blade disposed between the disc and the cover. A back surface of the disc has a recess extending in a circumferential direction in a radial range where the blade is disposed.

A method for forming a component for a gas turbine engine may include forming a first portion of the component that includes a cast metal or metal alloy, forming a second portion of the component that includes presintered preform defining at least one support structure, positioning the second portion on the first portion to define an assembly such that the first portion and the second portion define at least one cooling channel therebetween, and heating the assembly to join the first portion and the second portion and form the component.

An impeller for a centrifugal compressor, the impeller rotatable about a central axis, has: an outer hub body including a first material and extending around the central axis, the outer hub body defining a gaspath face extending from an inlet to an outlet, the gaspath face extending radially away from the central axis from the inlet to the outlet; blades protruding from the gaspath face and circumferentially distributed around the central axis; and an inner hub body extending around the central axis, the inner hub body secured to the outer hub body, the outer hub body axially overlapping and extending around the inner hub body, the inner hub body made of a second material being more cold dwell resistant than the first material.

An alpha-alumina coated turbocharger turbine wheel includes a hub portion, a plurality of blades disposed about the hub portion, each blade of the plurality of blades having a leading edge and a trailing edge, a centerline passing axially through the hub portion, and a back-side wall defined radially between the leading edge of each blade of the plurality of blades and the centerline. The turbocharger turbine wheel is made of a metal alloy and a surface coating layer of alpha-alumina. The surface coating layer of alpha-alumina may be disposed only on the hub portion, the plurality of blades, and a radially-outer portion of the back-side wall. The radially-outer portion is defined between a radial distance from the centerline and the leading edge of each blade of the plurality of blades. Alternatively, the surface coating layer of alpha-alumina may be disposed on the hub portion, the plurality of blades, and an entirety of the back-side wall.

A mixed-flow turbine wheel includes: a plurality of rotor blades disposed on a circumferential surface of the hub at intervals in a circumferential direction and configured such that each of the plurality of rotor blades has a leading edge which includes, in a meridional view, an oblique edge portion where a distance between the leading edge and an axis of the rotational shaft decreases from a tip side toward a hub side, and a sensor detection surface having a flat shape and being applied with a marking which is detectable by an optical sensor device. The sensor detection surface is formed on at least one of the circumferential surface of the hub or an edge portion of a reference rotor blade being one of the plurality of rotor blades, such that, in the meridional view, a trailing-edge side angle of two angles formed between the axis of the rotational shaft and a normal of the sensor detection surface is smaller than a trailing-edge side angle of two angles formed between the axis of the rotational shaft and a normal of the oblique edge portion.