Abstract: A turbine is provided with: a turbine wheel configured to rotate about an axis O1; a turbine housing accommodating the turbine wheel and defining an annular nozzle passage on the outer peripheral side of the turbine wheel; and a plurality of low solidity nozzle vanes 6 arranged in the nozzle passage at an interval in the circumferential direction. Circumferentially adjacent low solidity nozzle vanes 6 are disposed at different radial positions in a connection position of each of the low solidity nozzle vanes 6 with a hub-side wall surface of the hub-side wall surface and a shroud-side wall surface which define the nozzle passage.

Abstract: An impeller of a centrifugal compressor is an impeller 5 of a centrifugal compressor, that is, a compressor impeller 5 and includes a hub, at least one airfoil portion erected on a hub surface of the hub, and a first fillet. The at least one airfoil portion has a trailing edge configured such that a distance between the trailing edge and an axis of the centrifugal compressor increases with increasing distance from a back surface of the hub. The first fillet is formed on a radially outer side of an outer peripheral surface of a back plate portion forming a back surface portion of the hub. The first fillet connects the outer peripheral surface of the back plate portion and the trailing edge of the at least one airfoil portion.

Abstract: A turbine wheel according to at least one embodiment is a turbine wheel connected to a rotational shaft and configured to rotate about an axis and includes: a hub having a hub surface oblique to the axis in a cross-section along the axis; and a plurality of blades disposed on the hub surface. The turbine wheel includes a plurality of passages each of which is formed between two adjacent blades of the plurality of blades, and a relationship of Aen/Aave>1.01 is satisfied, where Aen is an area of a throat portion of a throat enlarged passage which is at least one of the plurality of passages, and Aave is an average area of throat portions of the plurality of passages.

Abstract: A surge suppression device for suppressing surge in an exhaust turbine-type turbocharger includes: a high-pressure tank configured to accumulate high-pressure gas with a higher pressure than atmospheric pressure; a high-pressure gas injection line connecting the high-pressure tank and an upstream intake passage on an upstream side of a compressor of the turbocharger; an on-off valve configured to open and close the high-pressure gas injection line; and a control device configured to control the on-off valve on the basis of a relationship between a pressure ratio of the compressor of the turbocharger and an intake flow rate.

Abstract: A turbine is provided with: a turbine wheel configured to rotate about an axis O1; a turbine housing accommodating the turbine wheel and defining an annular nozzle passage on the outer peripheral side of the turbine wheel; and a plurality of low solidity nozzle vanes 6 arranged in the nozzle passage at an interval in the circumferential direction. Circumferentially adjacent low solidity nozzle vanes 6 are disposed at different radial positions in a connection position of each of the low solidity nozzle vanes 6 with a hub-side wall surface of the hub-side wall surface and a shroud-side wall surface which define the nozzle passage.

Abstract: An impeller of a centrifugal compressor is an impeller 5 of a centrifugal compressor, that is, a compressor impeller 5 and includes a hub, at least one airfoil portion erected on a hub surface of the hub, and a first fillet. The at least one airfoil portion has a trailing edge configured such that a distance between the trailing edge and an axis of the centrifugal compressor increases with increasing distance from a back surface of the hub. The first fillet is formed on a radially outer side of an outer peripheral surface of a back plate portion forming a back surface portion of the hub. The first fillet connects the outer peripheral surface of the back plate portion and the trailing edge of the at least one airfoil portion.

Abstract: In a centrifugal compressor including an impeller rotatably disposed in a housing, the housing includes a shroud wall and a hub wall, which define a diffuser passage communicating with an outlet of the impeller. The diffuser flow passage includes a pinched part configured such that the shroud wall is closer to the hub wall radially outward of the centrifugal compressor from the outlet of the impeller, and a parallel part communicating with the pinched part on a radially outer side of the centrifugal compressor than the pinched part, the parallel part being configured such that the shroud wall and the hub wall are parallel to each other. The shroud wall has a surface facing the impeller and the hub wall, the surface having a cross-sectional shape where a tangent line exists at any position in a cross-section including an axis of the impeller.

Abstract: A rotor includes: a hub; and a plurality of blades disposed on the hub. Each of the plurality of blades has a suction surface, a pressure surface, a leading edge, a trailing edge, a tip-side edge, and a hub-side edge. The suction surface has a first curved surface portion curved convexly toward the trailing edge such that the trailing edge is inclined to a pressure surface side in a first region which is a partial region, in a blade height direction of the blade, of a region connected to the trailing edge.

Abstract: A rotor includes: a hub; and a plurality of blades disposed on the hub. Each of the plurality of blades includes a suction surface, a pressure surface, a leading edge, a trailing edge, a tip-side edge, and a hub-side edge. In a cross-section of each blade at a given chord position between the leading edge and the trailing edge, an angle of at least one of the suction surface or the pressure surface with respect to a blade height direction of the blade increases in a direction from the hub-side edge to the tip-side edge over a region from the hub-side edge to the tip-side edge, in at least a range from the leading edge to a chord position away from the leading edge toward the trailing edge.

Abstract: A centrifugal compressor includes: a housing; an impeller rotatably disposed within the housing; a rotational shaft connected to the impeller; and a bearing member supporting the rotational shaft in the housing. An oil flow passage through which oil flows is formed in the housing. The oil flow passage includes a lubricating oil passage through which the oil flows as lubricating oil to be supplied to the bearing member, and a cooling oil passage through which the oil flows as cooling oil for heat exchange with a fluid compressed by the impeller. The cooling oil passage is configured so that the oil flows into the cooling oil passage as the cooling oil without passing through the bearing member.

Abstract: A surge suppression device for suppressing surge in an exhaust turbine-type turbocharger includes: a high-pressure tank configured to accumulate high-pressure gas with a higher pressure than atmospheric pressure; a high-pressure gas injection line connecting the high-pressure tank and an upstream intake passage on an upstream side of a compressor of the turbocharger; an on-off valve configured to open and close the high-pressure gas injection line; and a control device configured to control the on-off valve on the basis of a relationship between a pressure ratio of the compressor of the turbocharger and an intake flow rate.

Abstract: In a centrifugal compressor including an impeller rotatably disposed in a housing, the housing includes a shroud wall and a hub wall, which define a diffuser passage communicating with an outlet of the impeller. The diffuser flow passage includes a pinched part configured such that the shroud wall is closer to the hub wall radially outward of the centrifugal compressor from the outlet of the impeller, and a parallel part communicating with the pinched part on a radially outer side of the centrifugal compressor than the pinched part, the parallel part being configured such that the shroud wall and the hub wall are parallel to each other. The shroud wall has a surface facing the impeller and the hub wall, the surface having a cross-sectional shape where a tangent line exists at any position in a cross-section including an axis of the impeller.

Abstract: A centrifugal compressor includes: a housing; an impeller rotatably disposed within the housing; a rotational shaft connected to the impeller; and a bearing member supporting the rotational shaft in the housing. An oil flow passage through which oil flows is formed in the housing. The oil flow passage includes a lubricating oil passage through which the oil flows as lubricating oil to be supplied to the bearing member, and a cooling oil passage through which the oil flows as cooling oil for heat exchange with a fluid compressed by the impeller. The cooling oil passage is configured so that the oil flows into the cooling oil passage as the cooling oil without passing through the bearing member.

Abstract: A rotor includes: a hub; and a plurality of blades disposed on the hub. Each of the plurality of blades includes a suction surface, a pressure surface, a leading edge, a trailing edge, a tip-side edge, and a hub-side edge. In a cross-section of each blade at a given chord position between the leading edge and the trailing edge, an angle of at least one of the suction surface or the pressure surface with respect to a blade height direction of the blade increases in a direction from the hub-side edge to the tip-side edge over a region from the hub-side edge to the tip-side edge, in at least a range from the leading edge to a chord position away from the leading edge toward the trailing edge.

Abstract: In a centrifugal compressor including an impeller rotatably disposed in a housing, the housing includes a shroud wall and a hub wall, which define a diffuser passage communicating with an outlet of the impeller. The diffuser flow passage includes a pinched part configured such that the shroud wall is closer to the hub wall radially outward of the centrifugal compressor from the outlet of the impeller, and a parallel part communicating with the pinched part on a radially outer side of the centrifugal compressor than the pinched part, the parallel part being configured such that the shroud wall and the hub wall are parallel to each other. The shroud wall has a surface facing the impeller and the hub wall, the surface having a cross-sectional shape where a tangent line exists at any position in a cross-section including an axis of the impeller.

Abstract: A rotor includes: a hub; and a plurality of blades disposed on the hub. Each of the plurality of blades has a suction surface, a pressure surface, a leading edge, a trailing edge, a tip-side edge, and a hub-side edge. The suction surface has a first curved surface portion curved convexly toward the trailing edge such that the trailing edge is inclined to a pressure surface side in a first region which is a partial region, in a blade height direction of the blade, of a region connected to the trailing edge.