Vane arrangement for a turbo-machine

A turbocharger comprising a turbine, the turbine having:

• a turbine housing defining a gas inlet;
• a turbine wheel positioned for rotation within the turbine housing about an axis;
• a ring-shaped shroud defining a plurality of slots and encircling the axis;
• and
• a nozzle ring supporting a plurality of vanes which extend from the nozzle ring parallel to the axis, and project through respective ones of the slots, each of the vanes being spaced from the axis by a nozzle radius;
• the shroud being coupled to the nozzle ring;
• each of the slots having an inwardly facing slot surface, and each of the vanes having an axially-extending vane surface which (i) a vane outer surface facing an outer surface of the corresponding slot, (ii) an opposed vane inner surface facing an inner surface of the corresponding slot, and (iii) a median line between the vane inner surface and the vane outer surface extending from a first end of the vane to a second end of the vane,
• the vane surface including a conformal portion, extending along at least 80% of the length of the median line, and facing a corresponding conformal portion of the slot surface, wherein, at room temperature, the respective profiles of the conformal portion of the vane surface and the conformal portion of the slot surface diverge from each other by no more than 0.35% of the nozzle radius.

A turbine for a turbocharger arranged to receive exhaust gas to drive a turbine wheel, the turbine having:

• a turbine housing defining a gas inlet;
• the turbine wheel positioned for rotation within the turbine housing about an axis;
• a ring-shaped shroud defining a plurality of slots and encircling the axis;
• and
• a nozzle ring supporting a plurality of vanes which extend from the nozzle ring parallel to the axis, and project through respective ones of the slots, each of the vanes being spaced from the axis by a nozzle radius;
• the shroud being coupled to the nozzle ring;
• each of the slots having an inwardly facing slot surface, and each of the vanes having an axially-extending vane surface which includes (i) a vane outer surface facing an outer surface of the corresponding slot, (ii) an opposed vane inner surface facing an inner surface of the corresponding slot, and (iii) a median line between the vane inner surface and the vane outer surface extending from a first end of the vane to a second end of the vane,
• the vane surface including a conformal portion, extending along at least 80% of the length of the median line, and facing a corresponding conformal portion of the slot surface, wherein, at room temperature, the respective profiles of the conformal portion of the vane surface and the conformal portion of the slot surface diverge from each other by no more than 0.35% of the nozzle radius defining a gap between the inwardly-facing slot surface and the vane surface that is smaller than a gap between portions of the inwardly-facing slot surface and the vane surface extending along the length of the conformal portions on the opposite side of the median line from the conformal portions.

A combination of a nozzle ring and shroud for a turbine of a turbocharger arranged to receive exhaust gas to drive a turbine wheel, the turbine having:

• a turbine housing defining a gas inlet, and configured to receive the nozzle ring and the shroud;
• and
• the turbine wheel positioned for rotation within the turbine housing;
• wherein:
• the shroud is coupled to the nozzle ring, is ring-shaped and defines a plurality of slots;
• and
• the nozzle ring supports a plurality of vanes which extend from the nozzle ring parallel to an axis of the nozzle ring, each of the vanes being spaced from the axis by a nozzle radius;
• each of the slots having an inwardly facing slot surface, and each of the vanes having an axially-extending vane surface which includes (i) a vane outer surface, (i) an opposed vane inner surface, and (iii) a median line between the vane inner surface and the vane outer surface extending from a first end of the vane to a second end of the vane;
• the vane surface including a conformal portion, extending along at least 80% of the length of the median line;
• the plurality of vanes being adapted for insertion into respective ones of the slots of the shroud with the corresponding vane outer surface facing an outer surface of the corresponding slot, the corresponding vane inner surface facing an inner surface of the corresponding slot, and the conformal portion of the vane surface facing a corresponding conformal portion of the slot surface;
• and
• wherein, at room temperature, the respective profiles of the conformal portion of the vane surface and the conformal portion of the slot surface diverge from each other by no more than 0.35% of the nozzle radius.