Dual-mode plug nozzle

Abstract

A variable geometry convergent-divergent nozzle for a gas turbine engine includes a centerbody extending rearward along a longitudinal axis of the engine which has a maximum diameter section. An inner shroud surrounds the centerbody and cooperates with the centerbody to define the throat of the nozzle. An outer shroud surrounds the inner shroud and cooperates with the centerbody to define the exit area of the nozzle. Both shrouds are independently translatable to provide independent control of the nozzle throat area and the nozzle expansion ratio. Additional actuation of the inner shroud results in the throat A8 being disposed upon a fully forward portion of the centerbody, said fully forward shroud disposition being more forward than over the maximum diameter section. The nozzle may further comprise independent translation of the centerbody 32 with respect to the shrouds.

Description

[0001] Statement on research & development initiated by the federal government [0002] According to Contract No. MDA972-01-3-0002 (DARPA) awarded by the U.S. Department of Defense, the U.S. government may have certain rights in this invention. [0003] Cross references to related applications [0004] This PCT utility application claims priority and benefits from the currently pending provisional application with US Patent Application Serial No. 61 / 829495, titled "Dual Mode Plug Nozzle", filed on May 31, 2013, The entirety of this application is incorporated herein by reference. Technical field [0005] The present invention relates generally to nozzles for gas turbine engines, and more particularly to nozzles of variable geometry that function as tapered nozzles, divergent nozzles, or tapered-divergent nozzles. Background technique [0006] In the exhaust system for gas turbine engines, the pressure ratio (ie, nozzle throat pressure / ambient pressure or P8 / P amb Under the condition...

AI Technical Summary

Problems solved by technology

However, systems that require two very different nozzle pressure ratios for a given nozzle throat area A8 for the engine cycle; such as, by way of illustration and not meant to be limiting, under one flight condition, P8 / P amb =2.5, under another flight condition, P8 / P amb =20.0, both conditions maintain nearly the same A8 value, the nozzle of such a system would not be able to achieve a geometry that would provide the desired performance for operation in these two flight conditions

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