Apparatus and method for controlling fan duct flow in a gas turbine engine

摘要

A fan duct flow control method and apparatus is provided for controlling fan bypass airflow at an inlet into an exhaust duct cooling annulus of a variable cycle gas turbine engine. The flow control employs a translating ring as a valve-like device that interacts with an annular lip on an inlet into the exhaust duct cooling annulus. The translating ring is positioned to restrict airflow into the liner during appropriate periods in engine operation. This flow control is uniquely constructed to be conveniently operated by a variable cycle engine actuation system that injects fan bypass air into an engine exhaust duct. The method and apparatus in one form is also used to block fan duct flow and reduce forward thrust during aircraft taxi operations.