Variable Area Nozzle Control Surface Actuation
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Solution Overview
Problem
Contemporary aircraft engine and nacelle structures face challenges in achieving optimal exhaust nozzle geometry across various flight phases, with existing solutions being complex and costly.
Innovation Solution
A turbine engine design featuring an inner and outer cowl with a movable control surface and actuator to adjust the nozzle's cross-sectional area, allowing for variable geometry between retracted and extended positions, thereby optimizing engine performance across different flight phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed geometry fan exhaust nozzle is used, then the structure is simple and cost-effective, but engine performance cannot be optimized across different flight phases
Solution Approach 1:
The exhaust nozzle transitions from a fixed geometry structure to a dynamic variable area nozzle. Control surfaces are mounted on the inner cowl and can pivot between a retracted position (larger cross-sectional area) and an extended position (smaller cross-sectional area), allowing the nozzle to adapt its geometry to different flight phases and optimize engine performance.
2Adaptability or versatility
If existing variable geometry solutions are implemented, then engine performance is improved, but the system becomes complex and costly
Solution Approach 1:
The control system is segmented into multiple independent control surfaces rather than using a complex monolithic mechanism. Each control surface can be independently actuated, allowing for simplified control architecture and reduced overall system complexity while still achieving variable geometry functionality.
Solution Approach 2:
The invention changes the geometric parameters of the exhaust nozzle by pivoting control surfaces between retracted and extended positions. This simple parameter change mechanism avoids the need for complex mechanical systems while effectively varying the nozzle cross-sectional area to optimize performance.
3Productivity
If traditional variable area nozzle systems are used, then performance is optimized, but weight increases and operational safety issues arise
Solution Approach 1:
The invention extracts and eliminates unnecessary components from traditional variable area nozzle systems. By using simple control surfaces that pivot on hinges mounted directly to the inner cowl, the design removes heavy mechanical actuation systems, linkages, and complex control mechanisms, thereby reducing weight while maintaining performance optimization capability.
Data Source
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AI summary
A turbine engine having an engine core, an inner cowl radially surrounding the engine core, an outer cowl radially surrounding the inner cowl and spaced from the inner cowl to form an annular passage between the inner and outer cowls that defines a nozzle, at least one control surface provided on the inner cowl and movable between a retracted position, where the nozzle has a first cross-sectional area, and an extended position where the nozzle has a second cross- sectional area that is less than the first cross-sectional area and an actuator operably coupled to the control surface and configured to move the control surface to control the cross-sectional area of the nozzle.