| 摘要 |
A jet engine nozzle operable in a cruise setting and a noise attenuation setting. In the cruise setting the nozzle provides simple through flow. In the noise attenuation setting some ambient flow is ducted into the through flow and some through flow is ducted into ambient flow. The nozzle comprises a fixed portion and a movable portion, rotatable a part of a revolution about the fixed portion. The nozzle comprises two rotary valves which operate in unison, a sleeve type valve and a face type. The sleeve type comprises cooperating lobed openings in the fixed portion and in a forward segment of the movable portion, the movable portion fitting telescopically over the fixed portion. The rotary type comprises the exit faces of aft facing lobes in the fixed portion and cooperating entrance faces of lobes in the aft segment of the movable portion. In the attenuation setting both valves are open. The sleeve valve ducts ambient flow into the flow through the nozzles and the face valve allows flow into ambient air from the flow through the nozzle. In the cruise setting both valves are closed. Opening and closing are powered by an appropriate state-of-the-art actuation apparatus and system and involve rotating the movable portion a part of a revolution so that either the various openings register with each other to make the valves open or register with structure which obstructs the opening and closes the valves, providing simple through flow. The nozzle may also be effectively used in modifying the infra-red signature of an engine.
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