Variable Area Fan Nozzle for Thrust Reversal Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gas turbine engines have limited control over thrust reversal force and lack additional functionality beyond landing operations due to their single thrust reversal position.
Innovation Solution
A variable area fan nozzle system that can move between multiple positions to control the cross-sectional area and direction of bypass air flow, allowing for enhanced thrust reversal control and additional operational functions such as aircraft maneuvering and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional thrust reverser with a single thrust reversal position is used, then the device structure is simple, but the control over thrust reversing force is limited
Solution Approach 1:
The patent applies the dynamics principle by making the fan nozzle area variable instead of fixed. The fan nozzle can dynamically adjust its cross-sectional area to multiple positions, enabling continuous control over the bypass air flow and thrust reversing force. This transforms the static thrust reverser into a dynamic system that can adapt to different operational requirements.
Solution Approach 2:
The patent implements parameter changes by varying the cross-sectional area of the fan nozzle. By changing the geometric parameter (nozzle area) of the bypass passage, the system controls the amount of bypass air flow that contributes to thrust reversal, thereby providing precise control over the reversing force magnitude.
2Device complexity
If a conventional thrust reverser is used, then the device is simple, but additional functionality outside of landing is not provided
Solution Approach 1:
The patent applies the universality principle by designing the variable area fan nozzle system to perform multiple functions beyond thrust reversal. The same nozzle mechanism provides thrust reversal during landing, thrust augmentation during takeoff, and noise reduction during cruise operations, making the system versatile and adaptable to various flight phases.
Solution Approach 2:
The dynamic adjustability of the fan nozzle area enables the system to adapt to different operational conditions. By dynamically changing the nozzle configuration, the system can optimize performance for thrust reversal, thrust augmentation, and noise reduction, providing multi-functionality without requiring separate dedicated systems for each operation.
3Ease of operation
If a variable area fan nozzle system is implemented, then control over thrust reversal force is precise, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the fan nozzle into multiple movable sections or segments that can be independently controlled. This segmentation allows the nozzle area to be adjusted in discrete steps or continuously, providing precise control over thrust reversal force while managing the complexity through modular design.
Solution Approach 2:
The patent introduces an intermediary control system (actuator mechanism) that mediates between the control input and the fan nozzle area adjustment. This intermediary component enables precise control of the nozzle position and area, translating control signals into accurate geometric changes without requiring direct manual adjustment of the complex nozzle structure.
4Force
If the bypass air flow is redirected for thrust reversal, then reverse thrust force is generated, but noise levels increase
Solution Approach 1:
The patent applies parameter changes by carefully controlling the bypass air flow parameters (flow rate, direction, and velocity) through the variable area fan nozzle. During cruise operations, the system adjusts these parameters to redirect exhaust gases over the wing, achieving noise reduction while maintaining beneficial aerodynamic effects. The parameter control allows the system to minimize noise-generating turbulence while still providing thrust management benefits.
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
The system provides precise control over thrust reversal force and additional functionality during cruise and landing conditions, improving aircraft control and reducing noise levels by varying the bypass air flow direction and pressure.
Implementation Method 1
A bypass air flow flows through a passage between the housing and the engine and exits from the engine at an outlet
Implementation Method 2
the fan nozzle is movable between a plurality of positions including a first thrust reverse position at which the fan nozzle deflects a portion of the bypass air flow in a forward direction to generate a reverse thrust
Data Source
Figure 1~2
Figure 3~4
AI summary
A gas turbine engine system comprises a nacelle (28), a gas turbine engine (10) within the nacelle (28), and a fan bypass passage (30) between the nacelle (28) and the gas turbine engine (10). A nozzle (40) having a cross-sectional area is associated with a bypass air flow through the fan bypass passage (30), the nozzle (40) having at least one section (40a) that is selectively moveable between a plurality of static positions for varying the cross-sectional and at least one thrust reverse position that is different from the plurality of static positions for reversing a direction of the bypass flow of the fan bypass passage (30). The system further comprises a controller (44) for selectively moving the at least one section (40a) responsive to one of a plurality of operational states of the gas turbine engine (10).