Variable Area Nozzle Pneumatic Actuation for Gas Turbine Engines
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Solution Overview
Problem
Existing gas turbine engines with variable area exhaust nozzles have complex and large actuation systems that hinder overall engine performance and aircraft integration.
Innovation Solution
A compact variable internal exhaust nozzle system utilizing a pneumatic circuit with convergent and divergent flap trains to manage flow streams, maintaining a fixed exit aperture while accommodating various flight conditions, using compressor bleed air to actuate flaps and control throat areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable area exhaust nozzle system is implemented to manage flow streams and control thrust, then engine performance across different flight conditions is improved, but the actuation system becomes large and complex
Solution Approach 1:
The patent combines the hydraulic actuation system and pneumatic actuation system into a single integrated nozzle assembly. The hydraulic system provides primary actuation force while the pneumatic system provides control and modulation, eliminating the need for separate actuation systems and reducing overall complexity.
Solution Approach 2:
The nozzle assembly is designed to perform multiple functions: thrust generation, flow management across different flight conditions, and integrated actuation. The same nozzle structure handles both military and civil flight regimes, and the integrated actuation system manages both hydraulic and pneumatic functions within a single assembly.
2Adaptability or versatility
If a variable area exhaust nozzle with multiple flow paths is used to accommodate different flight conditions, then adaptability is improved, but the system size and complexity increase
Solution Approach 1:
The nozzle is segmented into multiple flow paths including a military flow path and a civil flow path, allowing independent control of each path. This segmentation enables the nozzle to accommodate different flight conditions by selectively opening or closing specific flow paths, reducing the need for a completely variable geometry system.
Solution Approach 2:
The nozzle incorporates movable flaps and variable area sections that can dynamically adjust the flow paths based on flight conditions. The military flow path includes movable flaps for area control, while the civil flow path provides a fixed area exhaust, allowing the system to adapt between different operational regimes.
3Force
If hydraulic systems are used for actuating the nozzle flaps, then actuation force is sufficient, but the system requires separate hydraulic infrastructure increasing complexity
Solution Approach 1:
The patent merges the hydraulic actuation system and pneumatic control system into a single integrated nozzle assembly. The hydraulic system provides primary actuation force while the pneumatic system provides control and modulation, eliminating the need for separate actuation systems and reducing overall complexity.
Data Source
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AI summary
An exemplary nozzle having a variable internal exhaust area for a gas turbine engine can have a plurality of flap trains extending around a periphery of the gas turbine engine. Each flap train can include a convergent flap pivotally attached to an engine body and a divergent flap pivotally attached to the engine body downstream of the convergent flap. The nozzle can further have a fluid circuit in communication with the convergent and divergent flaps and configured to pivot the convergent and divergent flaps between a radially inward position and a radially outward position.