Thrust Vectorable Fan Variable Area Nozzle Segmentation
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Solution Overview
Problem
Aircraft turbofan gas turbine engines lack an effective and cost-efficient variable area nozzle for the fan nacelle, which is crucial for optimizing performance across different flight regimes, particularly in combat aircraft where high performance requirements increase complexity and weight.
Innovation Solution
A thrust vectorable fan variable area nozzle (FVAN) is implemented, comprising a synchronizing ring assembly, a static ring, and a flap assembly within the fan nacelle, allowing for independent rotation of segments to adjust the nozzle area, maximizing thrust and fuel economy by simultaneously adjusting the entire periphery or selectively vectoring thrust for trim balance and maneuvering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable area nozzle structure is incorporated for the fan air, then engine performance optimization across different flight regimes is achieved, but the expense, weight, and complexity of the nozzle structure increase
Solution Approach 1:
The nozzle structure is divided into multiple independently controllable segments or panels that can be adjusted individually or collectively. This segmentation allows the nozzle area to be varied to optimize performance for different flight regimes (takeoff, cruise, maneuvering) while using a modular approach that reduces overall structural complexity compared to a monolithic variable area nozzle.
Solution Approach 2:
The nozzle structure incorporates movable segments that can be dynamically adjusted during flight operations. This dynamic capability enables real-time optimization of the nozzle exit area according to changing flight conditions, allowing the engine to adapt between high thrust (takeoff) and fuel-efficient operation (cruise) without requiring multiple separate nozzle structures.
2Adaptability or versatility
If a variable area nozzle structure is incorporated for the fan air, then engine performance optimization is achieved, but the weight and expense increase
Solution Approach 1:
By dividing the nozzle into lighter-weight segmented panels rather than using a single heavy variable area nozzle structure, the overall weight is reduced while maintaining the capability to vary the exit area. The segmented design allows for more efficient use of material and easier integration with the existing fan nacelle structure.
3Productivity
If the entire periphery of the nozzle is adjusted simultaneously, then maximum engine thrust and fuel economy are optimized, but thrust vectoring capability for maneuvering is limited
Solution Approach 1:
The nozzle is divided into multiple independently controllable segments that can be adjusted individually. This segmentation enables the system to perform both symmetric adjustments (for optimizing thrust and fuel economy) and asymmetric adjustments (for thrust vectoring and maneuvering), providing full versatility without compromising either function.
Solution Approach 2:
The segmented nozzle structure serves multiple functions: it can be adjusted symmetrically to optimize engine performance for thrust and fuel economy, and asymmetrically to provide thrust vectoring for maneuvering and trim balance. This multi-functionality is achieved through the independent controllability of each segment, allowing a single structure to replace what would traditionally require separate systems for different functions.
Data Source
AI summary
A thrust vectorable fan variable area nozzle (FVAN) includes a synchronizing ring, a static ring, and a flap assembly mounted within a fan nacelle. An actuator assembly selectively rotates synchronizing ring segments relative the static ring to adjust segments of the flap assembly to vary the annular fan exit area and vector the thrust through asymmetrical movement of the thrust vectorable FVAN segments. In operation, adjustment of the entire periphery of the thrust vectorable FVAN in which all segments are moved simultaneously to maximize engine thrust and fuel economy during each flight regime. By separately adjusting the segments of the thrust vectorable FVAN, engine trust is selectively vectored to provide, for example only, trim balance or thrust controlled maneuvering.