An air turbine starter

摘要

A shroud (126) is provided for separating an air turbine starter housing from a turbine wheel (124). The shroud (126) comprises a ring (136) and a bumper (138). The ring (136) is configured to be disposed between the turbine wheel (124) and the housing and has an outer peripheral surface and an inner peripheral surface (143) that defines a flow channel (144). The bumper (138) is coupled to and extends radially inwardly from the ring inner peripheral surface (143) and defines a bumper section of the ring flow channel (144). At least a portion of the bumper section has a cross-sectional flow area that is less than another cross sectional flow area of the ring flow channel(144).