Exhaust Nozzle Translatable Structure for Thrust Reversal
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Solution Overview
Problem
Existing two-dimensional variable area exhaust nozzles for gas turbine engines are complex and lack simplified designs with thrust reversing capability and improved cruise efficiency.
Innovation Solution
A translatable structure within the exhaust duct is positioned to vary the flow diverting port and throat constriction, allowing for multiple operational positions that control the flow of exhaust gases, including full closure, full opening, and intermediate positions to optimize exhaust duct area and direct gases for thrust control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a two-dimensional variable area exhaust nozzle with thrust reversing capability is designed using conventional methods, then thrust reversing capability and variable nozzle exit area are achieved, but the mechanical system becomes complicated
Solution Approach 1:
The patent combines the thrust reversing function and variable area control into a single translatable structure that performs both functions simultaneously. The structure includes an inner door portion for flow diversion and an outer door portion for area control, which move together as one integrated assembly rather than separate mechanisms.
Solution Approach 2:
The translatable structure serves multiple functions: it controls the flow diverting port for thrust reversing, adjusts the nozzle exit area for efficiency, and defines the throat constriction position. This multi-functional design eliminates the need for separate mechanical systems for each function.
2Device complexity
If the exhaust nozzle design is simplified, then device complexity is reduced, but thrust reversing capability and cruise efficiency may be compromised
Solution Approach 1:
The nozzle employs a dynamic translatable structure that can be positioned in multiple locations along the exhaust duct to provide different operational modes. This dynamic positioning capability allows the simplified structure to achieve full thrust reversing, partial flow diversion, and variable area control that would otherwise require complex mechanisms.
Solution Approach 2:
The translatable structure is divided into functional portions (inner door portion, outer door portion, brace member) that work together cooperatively. This segmentation allows each portion to contribute to specific functions while maintaining overall structural simplicity and ease of translation.
3Adaptability or versatility
If the translatable structure is positioned to fully open the flow diverting port, then thrust reversing capability is maximized, but the cross-sectional area at the throat constriction decreases
Solution Approach 1:
The throat constriction position and area are dynamically adjusted based on the translatable structure's position. When the structure moves to enable flow diversion, the throat constriction automatically repositions to maintain optimal area, allowing the system to achieve both thrust reversing and efficient flow passage.
Data Source
AI summary
A method of operating an exhaust nozzle assembly includes translating a translatable structure between a plurality of operational positions to open and close a flow diverting port extending in an exhaust duct. The longitudinal position of a throat constriction varies with translation of the translatable structure. Additionally, the cross-sectional area of the exhaust duct at the throat constriction may vary with translation of the translatable structure. An exemplary exhaust nozzle is operable in-flight for providing at least partial reverse thrust to at least partly control the velocity of an aircraft. An exemplary exhaust nozzle is operable on the ground to spoil ground idle thrust.