Partial admission axial impulse turbine including cover for turbine wheel rotating assembly

摘要

A cover is affixed to a turbine housing on the downstream side of a turbine wheel rotating assembly to reduce a pumping loss inherently caused by a pressure gradient created by the turbine wheel blades when the turbine wheel rotates. A portion of an annular area on the exit face of the turbine wheel is left open for gas flow out of the blades being fed by the turbine nozzle or nozzles, with the remaining annular portion being covered with a close axial clearance with the turbine wheel rotating assembly to reduce the pumping loss.