Abstract: An afterburning, gas turbine aircraft engine with an annular duct for carrying bypass airflow is provided with a sliding valve type of rear Variable Area Bypass Injector (VABI) system. This rear VABI varies the direction and volume of the flow of bypass air into separate regions at an afterburning section of the engine. The system includes a sliding valve mounted in the bypass duct that is translated axially to open and close slots leading to core engine exhaust flow in the afterburning section. The unique structure of the injector system enables the axial translation of this sliding valve to simultaneously control bypass airflow into: first, a mixer just upstream of the afterburning section; second, a plurality of slots leading to the afterburning section; and third, an exhaust nozzle cooling liner that is cooled with the remaining portion of the bypass air.

Abstract: A design technique, method and apparatus for controlling the bypass gas stream pressure and varying the bypass ratio of a mixed flow gas turbine engine in order to achieve improved performance. The disclosed preferred embodiments each include a unique mixing device for combining the core and bypass gas streams which includes means for varying the area at which the bypass stream is injected into the core stream. The variable area mixing device permits the static pressures of the core and bypass streams to be balanced prior to mixing at widely varying bypass stream dynamic pressure levels.