Mixed-Flow Exhaust Nozzle with Independent Throat and Exit Control
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Solution Overview
Problem
Existing mixed flow exhaust nozzles for turbofan engines lack the ability to independently control the nozzle throat and exit areas, limiting their effectiveness in varying thrust reversal and aerodynamic performance.
Innovation Solution
An articulating exhaust nozzle with independent control of nozzle throat and exit areas through actuators, allowing for varying nozzle geometries to optimize thrust reversal and aerodynamic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing mixed flow exhaust nozzles are used, then the structure is simple, but the ability to independently control nozzle throat and exit areas is limited
Solution Approach 1:
The exhaust nozzle is divided into multiple independent controllable sections: an inner skin with a first articulation axis and an outer skin with a second articulation axis. This segmentation allows independent control of the nozzle throat area (via inner skin rotation) and nozzle exit area (via outer skin rotation), resolving the contradiction between adaptability and complexity by organizing the complex control function into modular, independent segments.
Solution Approach 2:
The nozzle transitions from a static structure to a dynamic, adjustable geometry through the incorporation of articulation axes and actuators. The inner and outer skins can rotate independently about their respective articulation axes, enabling real-time adjustment of both throat and exit areas. This dynamic capability provides the adaptability needed for varying thrust reversal and aerodynamic performance requirements.
2Productivity
If fixed nozzle geometry is used, then the structure is simple, but thrust reversal and aerodynamic performance are suboptimal
Solution Approach 1:
The nozzle geometry is made dynamically adjustable through the articulation system. The inner skin can rotate about the first articulation axis to optimize throat area for thrust reversal, while the outer skin rotates about the second articulation axis to optimize exit area for aerodynamic performance. This dynamic adaptability enables the nozzle to achieve optimal productivity across different flight conditions.
Solution Approach 2:
The nozzle controls its performance by changing geometric parameters (throat area and exit area) independently. Through the articulation mechanism, the system can vary the angles of the inner and outer skins, thereby changing the effective area parameters to optimize thrust reversal effectiveness and aerodynamic efficiency for different operational requirements.
3Adaptability or versatility
If single articulation axis is used, then the structure is simple, but independent control of throat and exit areas is not achieved
Solution Approach 1:
The articulation mechanism is segmented into two independent systems: an inner skin articulation system with a first articulation axis and an outer skin articulation system with a second articulation axis. This segmentation enables independent control of throat and exit areas respectively, achieving the desired adaptability while organizing the complexity into separate, manageable subsystems.
Solution Approach 2:
The system transitions from single-axis (one-dimensional) articulation to dual-axis (two-dimensional) articulation. By adding a second articulation axis for the outer skin, the system gains the freedom to control both throat and exit areas independently, effectively adding a dimension of control that enables the required adaptability.
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A
AI summary
An articulating exhaust nozzle thrust reverser includes an outer articulating panel (210) comprising an outer skin (212) and an outer thrust reverser door (214) and an inner articulating panel (220) comprising a forward inner skin (222), an aft inner skin (224), and an inner thrust reverser door (226). The outer articulating panel (210) is configured to pivot to vary a nozzle exit area. The forward inner skin (222) is configured to pivot to vary a nozzle throat area. The outer thrust reverser door (214) is pivotally coupled to the outer skin (212). The inner thrust reverser door (226) is pivotally coupled to the aft inner skin (224). The outer articulating panel (210) and the inner articulating panel (220) may be individually operated to independently vary the exhaust nozzle throat area and/or the exhaust nozzle exit area.