Variable flow area nozzle

Abstract

A variable flow area nozzle suitable for a gas turbine engine equipped with afterburning means comprises first and second ducts, the second duct pivotably mounted to the first and extending downstream from the first duct thereby defining a fluid flow therethrough. The first duct includes a lip which extends downstream through the second duct, the lip being of width corresponding to the internal width of the second duct thereby defining an exit orifice the flow area of which is controlled by the position of the second duct with respect to the lip. The nozzle further comprises a pressurizable chamber located on a side of the lip remote from the fluid flow path, the chamber being defined at least in part by the lip and a portion of the second duct. A vent hole in the lip is provided for admitting fluid into the chamber from fluid flow path. Fluid pressure in the pressurizable chamber exerts a force on the second duct to provide a moment about the pivotal mounting of the second duct which to an extent counteracts a moment exerted by the fluid flowing through the nozzle. A second pressurizable chamber may also be used for the same purpose.

Dependencies are inferred from the claim text.