Abstract: Contaminated air injected by an axial flow fan jet engine is treated by centrifuging the contamination through the surge bleed valves into the fan discharge stream in an efficient manner.

Abstract: An airfoil tip seal structure for an axial flow rotary machine is disclosed. Various concepts relating to seal designs and their influence on tip sealing effectiveness are discussed. In accordance with the teaching contained herein, one seal geometry includes a circumferentially extending groove in the stator which circumscribes the tips of the blades of a corresponding rotor stage. Another seal geometry applicable to machines having cantilevered stator vanes includes a circumferentially extending groove in the rotor which circumscribes the tips of the vanes of a corresponding stator stage. The tips of the blades and the tips of the cantilevered stator vanes run over the corresponding groove in line on line relationship with the adjacent flow path wall at the design operating condition of the machine in which the seal structure is incorporated.