Turbine with axial discontinuity

Abstract

A turbocharger turbine containing a separate insert affixed within the housing. The insert is of a stamped metal configuration, and forms at least a portion of inlet passageway outer wall. An axial discontinuity is machined into the inlet passageway outer wall, the axial discontinuity being characterized by a size and location to direct airflow away from the blade-gap zone over at least part of the range of flow conditions. The inlet passageway may be either larger or smaller upstream of the axial discontinuity.

1 . A turbocharger turbine insert for use as part of a turbocharger turbine configured to operate over a range of flow conditions, the turbine including a turbine housing including a body portion, and a turbine wheel within the housing, the wheel being characterized by an axis of rotation about which the wheel rotates, and the wheel having a plurality of blades, each blade forming a leading edge, a trailing edge and an outer edge, the outer edge extending from the leading edge to the trailing edge, wherein the path traveled by the outer edges of the blades through a rotation of the wheel defines an axially symmetric, smoothly varying, axially concave, outer-blade effective surface, wherein the housing and wheel define a fluid passageway serially including an inlet passageway and a blade passageway that extends from the blade leading edges to the blade trailing edges, the blade passageway being defined on an outer side by a shroud wall of the housing, wherein the inlet passageway is defined by an outer wall that is integral with the shroud wall, wherein a blade-gap zone is defined between the shroud wall and the outer-blade effective surface, and wherein the insert is a separate part of the housing that is produced by a process comprising the steps of:
 stamping a sheet of metal to form an insert configured to be affixed within the body portion of the housing to form at least a portion of inlet passageway outer wall; and   machining the insert to form an axial discontinuity in the inlet passageway outer wall, the axial discontinuity being characterized by a size and location to direct airflow away from the blade-gap zone over at least part of the range of flow conditions.   
     
     
         2 . The insert of  claim 1 , wherein the inlet passageway is larger upstream of the axial discontinuity. 
     
     
         3 . The insert of  claim 1 , wherein the inlet passageway is smaller upstream of the axial discontinuity. 
     
     
         4 . The insert of  claim 1 , wherein the discontinuity is immediately upstream of the leading edge. 
     
     
         5 . A turbocharger turbine configured to operate over a range of flow conditions, comprising:
 a turbine housing including a body portion;   a turbine wheel within the housing, the wheel being characterized by an axis of rotation about which the wheel rotates, and the wheel having a plurality of blades, each blade forming a leading edge, a trailing edge and an outer edge, the outer edge extending from the leading edge to the trailing edge, wherein the path traveled by the outer edges of the blades through a rotation of the wheel defines an axially symmetric, smoothly varying, axially concave, outer-blade effective surface;   wherein the housing and wheel define a fluid passageway serially including an inlet passageway and a blade passageway that extends from the blade leading edges to the blade trailing edges, the blade passageway being defined on an outer side by a shroud wall of the housing;   wherein the inlet passageway is defined by an outer wall that is integral with the shroud wall;   wherein a blade-gap zone is defined between the shroud wall and the outer-blade effective surface;   wherein the housing includes a separate insert affixed within the body portion of the housing, the insert being of a stamped metal configuration, the insert forming at least a portion of inlet passageway outer wall; and   wherein over at least part of the range of flow conditions, the insert forms an axial discontinuity in the inlet passageway outer wall, the axial discontinuity being characterized by a size and location to direct airflow away from the blade-gap zone.   
     
     
         6 . The turbocharger turbine of  claim 5 , wherein the inlet passageway is larger upstream of the axial discontinuity. 
     
     
         7 . The turbocharger turbine of  claim 5 , wherein the inlet passageway is smaller upstream of the axial discontinuity. 
     
     
         8 . The turbocharger turbine of  claim 5 , wherein the discontinuity is immediately upstream of the leading edge. 
     
     
         9 . A method of making a turbocharger turbine insert for use as part of a turbocharger turbine configured to operate over a range of flow conditions, the turbine including a turbine housing including a body portion, and a turbine wheel within the housing, the wheel being characterized by an axis of rotation about which the wheel rotates, and the wheel having a plurality of blades, each blade forming a leading edge, a trailing edge and an outer edge, the outer edge extending from the leading edge to the trailing edge, wherein the path traveled by the outer edges of the blades through a rotation of the wheel defines an axially symmetric, smoothly varying, axially concave, outer-blade effective surface, wherein the housing and wheel define a fluid passageway serially including an inlet passageway, and a blade passageway that extends from the blade leading edges to the blade trailing edges, the blade passageway being defined on an outer side by a shroud wall of the housing,
 wherein the inlet passageway is defined by an outer wall that is integral with the shroud wall, wherein a blade-gap zone is defined between the shroud wall and the outer-blade effective surface, and wherein the insert is a separate part of the housing, comprising the steps of:   stamping a sheet of metal to form an insert configured to be affixed within the body portion of the housing to form at least a portion of inlet passageway outer wall; and   machining the insert to form an axial discontinuity in the inlet passageway outer wall, the axial discontinuity being characterized by a size and location to direct airflow away from the blade-gap zone over at least part of the range of flow conditions.   
     
     
         10 . The method of  claim 9 , wherein the inlet passageway is larger upstream of the axial discontinuity. 
     
     
         11 . The method of  claim 9 , wherein the inlet passageway is smaller upstream of the axial discontinuity. 
     
     
         12 . The method of  claim 9 , wherein the discontinuity is immediately upstream of the leading edge. 
     
     
         13 . A turbocharger turbine configured to operate over a range of flow conditions, comprising:
 a turbine housing including a body portion;   a turbine wheel within the housing, the wheel being characterized by an axis of rotation about which the wheel rotates, and the wheel having a plurality of blades, each blade forming a leading edge, a trailing edge and an outer edge, the outer edge extending from the leading edge to the trailing edge, wherein the path traveled by the outer edges of the blades through a rotation of the wheel defines an axially symmetric, smoothly varying, axially concave, outer-blade effective surface;   wherein the housing and wheel define a fluid passageway serially including an inlet passageway and a blade passageway that extends from the blade leading edges to the blade trailing edges, the blade passageway being defined on an outer side by a shroud wall of the housing;   wherein the inlet passageway is defined by an outer wall that is integral with the shroud wall;   wherein a blade-gap zone is defined between the shroud wall and the outer-blade effective surface;   wherein over at least part of the range of flow conditions, the inlet passageway outer wall forms an axial discontinuity such that the inlet passageway is larger upstream of the axial discontinuity, the axial discontinuity being characterized by a size and location to direct airflow away from the blade-gap zone.   
     
     
         14 . The turbocharger turbine of  claim 13 , wherein the discontinuity is immediately upstream of the leading edge. 
     
     
         15 . The turbocharger turbine of  claim 13 , wherein the discontinuity comprises a sharp edge connecting a radially outward, upstream-facing face to a curving face downstream from the sharp edge.