A set of turbomachine guide vanes including plural vanes arranged around an annulus, each vane having a leading edge extending between root and tip ends, the leading edge offset between these two ends being greater than 10% of the blade height. A tangential stacking of the guide vanes towards the suction face side, the curve of tangential stacking, of the position, in the direction tangential to the annulus, of centers of gravity of successive vane cross sections along the vane height, is a curve that increases constantly towards the suction face side. The curve, near the vane tip end, has an accentuated gradient towards the suction face side compared with the rest of the curve, and has a mean gradient near the vane tip end that is greater than at least 1.2 times the mean gradient of the curve over the portion between 30% and 90% of the vane height.

A set of turbomachine guide vanes including plural vanes arranged around an annulus, each vane having a leading edge extending between root and tip ends, the leading edge offset between these two ends being greater than 10% of the blade height. A tangential stacking of the guide vanes towards the suction face side, the curve of tangential stacking, of the position, in the direction tangential to the annulus, of centers of gravity of successive vane cross sections along the vane height, is a curve that increases constantly towards the suction face side. The curve, near the vane tip end, has an accentuated gradient towards the suction face side compared with the rest of the curve, and has a mean gradient near the vane tip end that is greater than at least 1.2 times the mean gradient of the curve over the portion between 30% and 90% of the vane height.

An object is to provide an axial flow turbine of radial-inflow type whereby it is possible to suppress a decrease in turbine efficiency due to tip leakage, and a turbocharger having the same. An axial flow turbine of radial-inflow type includes a housing having a scroll part for swirling working fluid flowing into the housing (40) along a circumferential direction of a rotation shaft and a bend part (52) for changing a flow direction of the working fluid flowing inwardly in the radial direction from the scroll part into a direction along the axial direction to direct the working fluid to turbine blades (30). The bend part includes a tip-side inner wall surface (60) of a bend shape at least in a region at an upstream side, in the axial direction, of a portion (36H) of a leading edge (36) of the turbine blades, the portion being adjacent to a hub. The bend shape of the tip-side inner wall surface along the axial direction has a minimum curvature radius R.sub.min at a position X.sub.Z near the turbine blades, and a curvature radius R (>R.sub.min) at the upstream side of the position X.sub.Z.

An object is to provide an axial flow turbine of radial-inflow type whereby it is possible to suppress a decrease in turbine efficiency due to tip leakage, and a turbocharger having the same. An axial flow turbine of radial-inflow type includes a housing having a scroll part for swirling working fluid flowing into the housing (40) along a circumferential direction of a rotation shaft and a bend part (52) for changing a flow direction of the working fluid flowing inwardly in the radial direction from the scroll part into a direction along the axial direction to direct the working fluid to turbine blades (30). The bend part includes a tip-side inner wall surface (60) of a bend shape at least in a region at an upstream side, in the axial direction, of a portion (36H) of a leading edge (36) of the turbine blades, the portion being adjacent to a hub. The bend shape of the tip-side inner wall surface along the axial direction has a minimum curvature radius R.sub.min at a position X.sub.Z near the turbine blades, and a curvature radius R (>R.sub.min) at the upstream side of the position X.sub.Z.

A method and a turbine for expanding an organic operating fluid in a Rankine cycle includes the step of feeding the operating fluid to a turbine provided with a plurality of arrays of stator blades alternating with a plurality of arrays of rotor blades, to define corresponding turbine stages, constrained to a shaft which rotates on the respective rotation axis. The method also includes: a) causing a first expansion of the operating fluid in one or more radial stages of the turbine, b) diverting the operating fluid exiting from the radial stages in a direction axial and tangential with respect to the rotation axis, and c) causing a second fluid expansion in one or more axial stages of the turbine. Step b) corresponds to an enthalpy change of the operating fluid equal to at least 50% of the average enthalpy change provided for completing the fluid expansion in the turbine.

A method and a turbine for expanding an organic operating fluid in a Rankine cycle includes the step of feeding the operating fluid to a turbine provided with a plurality of arrays of stator blades alternating with a plurality of arrays of rotor blades, to define corresponding turbine stages, constrained to a shaft which rotates on the respective rotation axis. The method also includes: a) causing a first expansion of the operating fluid in one or more radial stages of the turbine, b) diverting the operating fluid exiting from the radial stages in a direction axial and tangential with respect to the rotation axis, and c) causing a second fluid expansion in one or more axial stages of the turbine. Step b) corresponds to an enthalpy change of the operating fluid equal to at least 50% of the average enthalpy change provided for completing the fluid expansion in the turbine.

A steam turbine, having a steam turbine outer housing; a high-pressure inner housing having first process steam inlet and outlet sections for conducting process steam therethrough from the inlet to the outlet section in a first process steam expansion direction; a low-pressure inner housing having second process steam inlet and outlet sections for conducting process steam therethrough from the second process steam inlet section to the second process steam outlet section in a second process steam expansion direction; and an intermediate superheater, which is arranged downstream of the high-pressure inner housing and upstream of the low-pressure inner housing, wherein the high-pressure and low-pressure inner housings are arranged within the steam turbine outer housing and the high-pressure and the low-pressure inner housings are arranged in such a way that the first steam inlet section of the high-pressure inner housing faces the second steam inlet section of the low-pressure inner housing.

A powered augmented fluid turbine for generating electricity from a fluid in motion comprising: a central annular ducted channel extending between an inlet distribution header and an outlet distribution header, the channel comprising a converging section configured to accelerate the fluid received at the inlet distribution header, a turbine assembly for generating electricity, and a diffuser section configured to decelerate the fluid before it exits at the outlet distribution header; a recycle line for transporting the exiting fluid to the inlet distribution header in a closed-loop configuration, the recycle line comprising a recycle line propulsor controllable by a recycle line controller and a recycle line heat exchanger; and a compressed fluid distribution line configured to pressurize the fluid in motion by transporting a compressed fluid from a compressed fluid source to the inlet and outlet distribution headers, the compressed fluid distribution line controllable by at least one pressure controller.

A powered augmented fluid turbine for generating electricity from a fluid in motion comprising: a central annular ducted channel extending between an inlet distribution header and an outlet distribution header, the channel comprising a converging section configured to accelerate the fluid received at the inlet distribution header, a turbine assembly for generating electricity, and a diffuser section configured to decelerate the fluid before it exits at the outlet distribution header; a recycle line for transporting the exiting fluid to the inlet distribution header in a closed-loop configuration, the recycle line comprising a recycle line propulsor controllable by a recycle line controller and a recycle line heat exchanger; and a compressed fluid distribution line configured to pressurize the fluid in motion by transporting a compressed fluid from a compressed fluid source to the inlet and outlet distribution headers, the compressed fluid distribution line controllable by at least one pressure controller.

An exhaust-gas turbocharger for a motor vehicle includes a compressor, a first and a second axial turbine, an electrical generator and an electric motor. The axial turbines are configured to drive the generator. The generator is configured to provide a feed to the electric motor. The electric motor is configured to drive the compressor.