Apparatus for compressor air extraction
AssigneeGeneral Electric Company
InventorsJohn L. Baughman, Rollin G. Giffin, III
Life of this patent
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Abstract
A method of obtaining extraction airflow from a compressor includes accelerating the extraction airflow to at least Mach 1 for obtaining choked airflow and decelerating the choked airflow to a speed less than Mach 1. An apparatus for carrying out the method includes a compressor casing having an extraction airflow port, first means for accelerating the extraction airflow channeled through the port to at least Mach 1 for obtaining choked airflow, and means for decelerating the choked airflow to a speed less than Mach 1. In an exemplary embodiment, a converging-diverging nozzle is provided for accelerating the extraction airflow to at least Mach 1 and then declerating the choked airflow.
Claims37
A compressor air extraction assembly for a gas turbine engine comprising:
- a compressor casing for surrounding a row of circumferentially spaced compressor blades extending from a rotatable shaft and defining a flow channel for receiving compressor airflow comprising air compressed by said blades;
- said casing including a continuously open port disposed downstream of at least a row of said blades for receiving a portion of said compressed air as extraction airflow;
- an extraction channel coupled between said port and a bypass duct, said channel including first means for accelerating to Mach 1 said extraction airflow channeled through said port and establishing in said channel choked airflow of said extraction air;
- and means within said channel coupled to said first accelerating means for decelerating said choked airflow in said channel to a speed less than Mach 1 for obtaining subsonic airflow;
- and means coupled to said decelerating means for discharging said subsonic airflow as discharged airflow into said bypass duct, wherein the choked airflow in the channel regulates the airflow through said port and prevents extraction airflow from increasing substantially relative to compressor airflow as compressor speed decreases.
A compressor extraction assembly for a gas turbine engine, the compressor extraction assembly capable of maintaining a relatively constant airflow over a range of speeds of a gas turbine engine high pressure compressor and directing extraction air from the compressor into a bypass duct, comprising:
- a compressor casing for surrounding a row of circumferentially spaced compressor blades extending from a rotatable shaft and defining a flow channel for receiving air compressed by said blades;
- said casing including a continuously open port disposed downstream of at least a row of said blades for receiving a portion of said compressed air as extraction airflow, said casing port being annular and having an annular upstream edge and an annular downstream edge spaced from said upstream edge;
- an annular first flowpath surface extending downstream from said port upstream edge;
- an annular second flowpath surface extending downstream from said port downstream edge and spaced from said first flowpath surface;
- a plurality of circumferentially spaced struts extending from said first to said second flowpath surfaces;
- first means for accelerating said extraction airflow channeled through said port to Mach 1 for obtaining choked airflow of said extraction air, said means including a converging nozzle having an inlet for receiving said extraction airflow, and a throat of minimum flow area;
- second means for accelerating said choked airflow to a speed greater than Mach 1 for obtaining supersonic airflow, said second accelerating means including a diverging nozzle having an upstream portion extending from said throat to an intermediate section;
- means for decelerating said choked airflow to a speed less than Mach 1 for obtaining subsonic airflow, said decelerating means including said diverging nozzle having a downstream portion extending from said intermediate section to an outlet;
- means for discharging said subsonic airflow as discharged airflow, said discharging means including said outlet of said diverging nozzle downstream portion;
- and
- said first and said second flowpath surfaces defining therebetween said converging nozzle, throat, and diverging nozzle in flow communication with said port.
Dependencies are inferred from the claim text.