Gas turbine engine variable area exhaust nozzle

摘要

A turbofan gas turbine engine (10) comprises a variable area exhaust nozzle (12) arranged at the downstream end of a casing (17). A control unit (66) analyzes the power produced by the gas turbine engine (10), the flight speed of the gas turbine engine (1) and/or the altitude of the gas turbine engine (10). The control unit (66) configures the variable area nozzle (12) at a first cross-sectional area (70A) when the flight speed of the gas turbine engine (10) is less than a first predetermined value. The control unit (66) configures the variable area nozzle (12) at a second, smaller, cross-sectional area (70B) when the flight speed of the gas turbine engine (10) is greater than the first predetermined value and the power produced by the gas turbine engine (10) is greater than a second predetermined value. The control unit (66) configures the variable area nozzle (12) at a third, intermediate, cross-sectional area (70C) when the flight speed of the gas turbine engine (10) is greater than the first predetermined value and the power produced by the gas turbine engine (10) is less than the second predetermined value.

主权项

1. A gas turbine engine comprising:
a casing defining a flow passage through the gas turbine engine; a variable area exhaust nozzle being arranged at the downstream end of the casing, the variable area exhaust nozzle having a downstream end and a cross-sectional area measured at the downstream end of the variable area exhaust nozzle; a power sensor configured to measure the power produced by the gas turbine engine; a flight speed sensor configured to measure the flight speed of the gas turbine engine or an altitude sensor configured to measure the altitude of the gas turbine engine; a control device configured to receive measurements of the power produced by the gas turbine engine, the flight speed of the gas turbine engine or the altitude of the gas turbine engine, the control device configured to analyse the power produced by the gas turbine engine, the flight speed of the gas turbine engine or the altitude of the gas turbine engine, the control device configured to configure the cross-sectional area of the variable area exhaust nozzle at a first cross-sectional area in a first mode of operation when the control device determines that the flight speed of the gas turbine engine or the altitude of the gas turbine engine is less than a first predetermined value, the control device configured to configure the cross-sectional area of the variable area exhaust nozzle at a second cross-sectional area that is greater than zero in a second mode of operation when the control device determines that the flight speed of the gas turbine engine or the altitude of the gas turbine engine is equal to or greater than the first predetermined value and the power produced by the gas turbine engine is equal to or greater than a second predetermined value, and the control device is arranged to configure the cross-sectional area of the variable area exhaust nozzle at a third cross-sectional area in a third mode of operation when the control device determines that the flight speed of the gas turbine engine or the altitude of the gas turbine engine is equal to or greater than the first predetermined value and the power produced by the gas turbine engine is less than the second predetermined value, wherein the second cross-sectional area is less than both the first cross-sectional area and the third cross-sectional area and the third cross-sectional area is less than the first cross-sectional area.