Plug-type exhaust nozzle having a variable centerbody and translating shroud

摘要

A variable geometry gas turbine engine exhaust nozzle includes a variable circumference centerbody and a translating, annular shroud that cooperate to vary the throat area of the exhaust nozzle and the final area of the exhaust gas exiting the nozzle. The shroud includes a substantially constant inside diameter forward portion and a rear portion that has a continuously increasing inside diameter in the rearward direction. The centerbody is coaxially positioned within a circular cross section flow passage formed by the shroud and is configured with an upper and a lower shell that pivot between a retracted and an extended position. In the retracted position, the centerbody presents a circular profile to exhaust gases flowing through the exhaust nozzle. In the extended position, the centerbody presents an oval profile. By coordinating the centerbody shell position with the axial position of the shroud, the throat passage of the exhaust nozzle can be varied between an annular and a nonannular cross section. Additionally, since the shroud can be moved translationally independently of the configuration of the centerbody, the throat area of the exhaust nozzle and the final area of the exhaust gas can be varied independently of one another.