Variable Area Fan Nozzle Actuator Flap Mechanism
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Solution Overview
Problem
Existing gas turbine engines lack the ability to efficiently vary the cross-sectional area of fan nozzles to adapt to different flight conditions and operational requirements, such as varying power levels and cooling needs.
Innovation Solution
A variable area fan nozzle system is implemented, featuring a heat exchanger positioned between the follower and actuator flaps, with an actuator that controls the movement of the follower flap to adjust airflow across the heat exchanger, allowing for varying airflow based on different positions, including a thrust reverser position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fan nozzle area is fixed, then the engine structure is simple, but the engine cannot adapt to different flight conditions and power levels
Solution Approach 1:
The patent applies the dynamics principle by making the nozzle area variable instead of fixed. The follower flap and actuator flap can move relative to each other to change the nozzle cross-sectional area, allowing the engine to adapt to different flight conditions and power levels while maintaining a relatively simple structural implementation.
2Temperature
If the follower flap is moved to allow airflow across the heat exchanger, then cooling efficiency is improved, but the nozzle area control complexity increases
Solution Approach 1:
The patent merges the cooling function with the nozzle area control function. The follower flap serves dual purposes: it controls the nozzle throat area for power level adjustment and simultaneously controls airflow across the heat exchanger for cooling. This integration eliminates the need for separate cooling control mechanisms, reducing overall system complexity.
Solution Approach 2:
The follower flap is designed as a multi-functional component that performs both nozzle area regulation and cooling airflow control. By positioning the heat exchanger between the follower flap and actuator flap, the follower flap's movement simultaneously achieves both functions, demonstrating universal application of a single component.
3Adaptability or versatility
If separate thrust reversers are used, then thrust reversal function is achieved, but the device complexity and space requirements increase
Solution Approach 1:
The patent combines the thrust reversal function with the existing variable area nozzle mechanism. The actuator flap can be moved to a thrust reverser position where it blocks the nozzle area, redirecting exhaust flow for thrust reversal. This integration eliminates the need for separate thrust reverser components, reducing device complexity and space requirements.
Solution Approach 2:
The actuator flap is designed to perform multiple functions: normal nozzle area control during engine operation and thrust reversal when positioned in the stop position. This multi-functionality allows a single component to replace what would traditionally require separate systems for nozzle control and thrust reversal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables efficient adaptation of fan nozzle area to different flight conditions, optimizing power output and cooling efficiency, while also eliminating the need for separate thrust reversers, thereby enhancing engine performance and operational flexibility.
Implementation Method 1
a heat exchanger positioned between the follower and actuator flaps
Implementation Method 2
the actuator is configured to move the follower flap to control airflow across the heat exchanger
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
A variable area fan nozzle (100) comprises an actuator flap (114) and a follower flap (106). The actuator flap (114) has a portion in contact with a portion of the follower flap (106). A bias member (112) biases the follower flap (114) outwardly. An actuator (120) actuates the actuator flap (114) inwardly and outwardly to, in turn, move the follower flap (106) against the bias member (112) and to vary an area of an exhaust nozzle. The flap actuator (120) is operable to drive the actuator flap (114) out of contact with the follower flap (106) into a thrust reverser position.