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.

Provided are a variable geometry turbine and a supercharger including the same that can change flow rate characteristics of a turbine in accordance with engine output with simple structure and can adjust the flow angle of a fluid flowing into a turbine impeller to any angle in the circumferential direction of the turbine impeller. The variable geometry turbine (10) includes a turbine impeller (12) configured to rotate about an axis line, a turbine housing (30) configured to accommodate the turbine impeller (12) and form a throat passage (32) and a scroll flow channel (34) on the outer circumferential side of the turbine impeller (12), the scroll flow channel (34) communicating with the throat passage (32), and a width changing mechanism in which a width change portion (52) that changes a passage width of the throat passage (32) along the circumferential direction of the turbine impeller (12) is movable in the width direction of the passage width.

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.

A turbine rotor includes a base and a plurality of blades. A central nose is radially inward of the blades and defines an axis of rotation. A plurality of cooling manifolds is disposed within the turbine rotor and includes impingement cooling jets extending through a rear surface of the turbine rotor. An internal cooling manifold extends radially inward of the impingement cooling jets and extends between the base and the rear surface of the turbine rotor. A central nose cooling manifold extends into the central nose and is fluidically connected to the internal cooling manifold. A base cooling manifold is fluidically connected to the central nose manifold and extends radially outward from the central nose cooling manifold. A blade cooling manifold is fluidically connected to the base cooling manifold and extends within the blade. Trailing edge jets extend from the blade cooling manifold and through the trailing edge of blades.

In a turbine designing and manufacturing method attendant on a material change of a rotor disk of a turbine rotor, a temperature rise time ratio is determined which is a desired ratio of a temperature rise time of the temperature of the rotor disk from a first temperature to a second temperature after the material change to the temperature rise time before the material change. An inter-surface distance between surfaces on upstream and downstream sides of the rotor disk after the material change is determined, and a shape of the rotor disk after the material change is determined based on the inter-surface distance. The turbine is designed based on the determined shape of the rotor disk. After the material change in the shape determined in the designing process, the rotor disk and the turbine are manufactured based on the result of the designing process.

In a turbine designing and manufacturing method attendant on a material change of a rotor disk of a turbine rotor, a temperature rise time ratio is determined which is a desired ratio of a temperature rise time of the temperature of the rotor disk from a first temperature to a second temperature after the material change to the temperature rise time before the material change. An inter-surface distance between surfaces on upstream and downstream sides of the rotor disk after the material change is determined, and a shape of the rotor disk after the material change is determined based on the inter-surface distance. The turbine is designed based on the determined shape of the rotor disk. After the material change in the shape determined in the designing process, the rotor disk and the turbine are manufactured based on the result of the designing process.

Provided is a turbocharger with further improved thermal efficiency. The turbocharger includes a heat shielding plate disposed between a center housing and a turbine housing. The center housing rotatably and pivotally supports a rotating shaft that connects a turbine impeller and a compressor impeller, and the turbine housing houses the turbine impeller. The turbocharger includes: a first flange portion; a second flange portion formed corresponding to the first flange portion; a clamp member combining the first flange portion and the second flange portion and fixing the mutual positional relationship; and a heat insulating ring interposed between an end surface, which is a heat shielding plate fixing portion that fixes the heat shielding plate, and the heat shielding plate on an inner peripheral side with respect to the first flange portion and the second flange portion.

A turbine (3) includes: a turbine impeller chamber (43) having a tubular outflow portion (432), from which an exhaust gas flows out in an outflow direction (F) substantially parallel to an axis (C) of a turbine impeller (5); a bypass flow passage (491) bypassing the inside of the turbine impeller chamber; an outer duct (47) having an inner peripheral surface (475) that expands in diameter in the outflow direction from the outflow portion; and an inner duct (48) that extends in the outflow direction from the outflow portion. A diffuser flow passage (483) that expands in diameter in the outflow direction is disposed in the inner duct at least in a portion between the outflow portion and a distal end portion (481a). An outlet (492) of the bypass flow passage and a waste gate valve (493) that opens and closes the outlet are disposed on the inner peripheral surface.

A rotating machine includes a hub portion, wherein the hub portion comprises a forward face and an aft face. The rotating machine further includes a cooling channel formed on either the forward face or the aft face and configured to direct cooling air to a location on the rotating machine, wherein the cooling channel extends from a radially inner location along the face to a radially outer location along the face, and wherein the cooling channel is configured as a recess formed into an outer surface of the face.

A rotating machine includes a hub portion, wherein the hub portion comprises a forward face and an aft face. The rotating machine further includes a cooling channel formed on either the forward face or the aft face and configured to direct cooling air to a location on the rotating machine, wherein the cooling channel extends from a radially inner location along the face to a radially outer location along the face, and wherein the cooling channel is configured as a recess formed into an outer surface of the face.