Cascade Variable Area Fan Duct Nozzle Weight Reduction
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Solution Overview
Problem
Existing aircraft nacelles with variable area fan duct nozzles face challenges due to the added weight of electrical and mechanical components, which hinder noise reduction and fuel efficiency improvements, especially in high-bypass turbofan engines and geared turbofan engines.
Innovation Solution
The design incorporates a translating panel and cascade guide vane panel actuated by an actuator, allowing the nozzle area to be varied by positioning guide vanes between inner and outer walls to direct airflow outward and aftward, reducing the need for heavy mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrical and mechanical components are used to vary nozzle area in VAFN systems, then nozzle area can be modulated for noise reduction and fuel efficiency, but the aircraft weight increases
Solution Approach 1:
The patent extracts and removes the heavy electrical and mechanical components from the VAFN system, retaining only the essential functional elements. The nozzle area is varied using a simplified mechanism that eliminates complex actuators and control systems, thereby achieving noise reduction and fuel efficiency benefits without the weight penalty of conventional VAFN systems.
Solution Approach 2:
The patent employs a dynamic translating panel that can move between positions to vary the nozzle area. This dynamic structure allows the nozzle to adapt its opening area in real-time for optimized performance during different flight phases, while the panel itself serves as both the flow boundary and the actuation mechanism, eliminating the need for separate heavy mechanical components.
2Device complexity
If a translating panel is used to vary nozzle area, then the structure becomes simpler and lighter, but the device complexity increases due to the actuation mechanism
Solution Approach 1:
The patent merges the translating panel with the cascade guide vane panel, combining two functional elements into a single integrated structure. This consolidation simplifies the overall device by reducing the number of separate components and their associated actuators, while the unified panel can be actuated by a single mechanism that controls both the panel translation and guide vane positioning.
Solution Approach 2:
The translating panel serves multiple functions: it acts as a flow boundary defining the nozzle area, provides structural support for the cascade guide vanes, and serves as the actuated element for area variation. This multi-functionality reduces the need for separate components and simplifies the overall system, making the device easier to operate with fewer control mechanisms required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances noise reduction and fuel efficiency by varying the nozzle area without increasing the aircraft's weight, enabling efficient airflow modulation and thrust vectoring.
Implementation Method 1
The guide vanes may be angled and configured to direct airflow from within the inner wall in an outward and aftward direction relative to the outer wall in the deployed position
Data Source
AI summary
An aircraft nacelle comprising an outer cowl having an inner wall and an outer wall surrounding the inner wall. The inner wall may have an inner opening formed therethrough and the outer wall may have an outer opening formed therethrough at an aft end of the nacelle. The nacelle may further comprise a translating panel configured to cover the inner and outer openings in a stowed position and to translate aft to a deployed position. The translating panel may be fixed to cascade guide vane panels which rest between the inner and outer wall in the stowed position and are exposed to airflow via the inner and outer openings when translated aft to the deployed position, thereby increasing a nozzle area of the nacelle. Guide vanes of the cascade guide vane panels are angled slightly aftward to direct the nacelle's airflow outward and aftward.