Abstract: A method and apparatus for controlling the amount of gas flow through a compressor having variable geometry guide vanes and a variable geometry diffuser. The geometry variation of the diffuser is based on the geometry variation of the guide vanes. The method and apparatus ensure that the compressor will operate at peak efficiency over a broad range of load conditions.

Abstract: A multiple bypass turbofan engine including a core engine assembly has a fan bypass duct radially outward of the core engine assembly and has first and second inlets disposed between forward and aft fans driven by a low pressure turbine and a core engine turbine respectively. An inlet duct having an annular duct wall is disposed radially inward of the bypass duct and connects the second inlet to the bypass duct and has disposed within a supercharger means for compressing air which is drivingly connected to the core turbine. One embodiment of the aft fan may have radially inner and outer rows of aft fan vane airfoils separated by a non-rotatable portion of the annular duct wall such that the outer row of aft fan vane airfoils are disposed in the inlet duct and at least one of the aft fan vane airfoils is and, preferably, all of which are, independently variable.

Abstract: A variable pipe diffuser for use in a centrifugal compressor. The variable pipe diffuser includes an outer ring and an inner ring which is rotatable circumferentially within the outer ring between a first, open position and a second, closed position. In an open position, complementary air channel sections of the inner and outer rings are aligned with one another to allow a maximum flow of refrigerant through the diffuser. In a closed position, the flow channels of the ring sections are misaligned and the flow of refrigerant through the diffuser is restricted. By adjusting the diffuser rings toward a closed position, surge conditions can be avoided even in the case where a high compressor pressure ratio is required.

Abstract: A centrifugal compressor having an impeller wheel mounted for rotation about a central axis and a diffuser for emptying compressed fluid into a collector chamber. A plenum chamber is located behind the impeller shroud and series of deswirl passages are located about the impeller for placing the collector chamber in fluid flow communication with the plenum chamber. A series of channel flow passages are further arranged to inject compressor fluid in the plenum chamber into the exit flow leaving the tips of impeller blades under controlled conditions so that the injected fluid enters the exit flow smoothly and with little loss of energy. An adjustable control device regulates the flow through the deswirl passages to keep the total flow moving through the diffuser relatively constant under varying load conditions.