Rotating Nacelle Inlet Structure for Variable Airflow Across Flight Modes
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Solution Overview
Problem
Existing aircraft propulsion system inlet structures lack the ability to efficiently adjust airflow inlet area to accommodate varying mass flow requirements based on flight modes and operating conditions.
Innovation Solution
A nacelle inlet structure with a movable and static configuration that allows for a variable airflow inlet area, featuring a movable structure that rotates to open and close discrete inlet openings, enabling adjustment of airflow based on supersonic and subsonic flight modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed inlet area is used, then the inlet structure is simple and reliable, but it cannot accommodate varying mass flow requirements across different flight modes
Solution Approach 1:
The inlet structure employs a movable vane that can rotate between different positions to dynamically adjust the inlet area. The vane is actuated by a control system that responds to flight conditions, enabling the inlet to adapt between supersonic and subsonic operating modes. This dynamic adjustment mechanism resolves the contradiction by providing variability in inlet area while maintaining a relatively simple overall structure.
Solution Approach 2:
The inlet structure is divided into discrete components including a movable vane, stationary vanes, and inlet openings. This segmentation allows the inlet area to be adjusted by positioning the movable vane at different angles, creating variable flow passages. The segmented design enables adaptability to different mass flow requirements while keeping each individual component simple and manageable.
2Productivity
If the inlet area is increased to accommodate higher mass flow, then propulsion efficiency improves, but the inlet structure becomes more complex
Solution Approach 1:
The movable vane dynamically adjusts the inlet area based on propulsion demands. When higher mass flow is required, the vane rotates to open a larger inlet area, maximizing air intake capacity. When lower mass flow is sufficient, the vane closes or partially closes the inlet. This dynamic control enables the inlet to achieve high productivity when needed while maintaining structural simplicity through a single adjustable component.
Solution Approach 2:
The movable vane serves multiple functions: it controls inlet area, directs airflow, and adapts to different flight modes. This multi-functionality allows the inlet structure to achieve variable mass flow capacity without requiring separate mechanisms for each function, thereby avoiding increased complexity while maintaining high productivity capability.
3Adaptability or versatility
If a movable structure is added to enable variable inlet area, then adaptability to flight modes improves, but device complexity increases
Solution Approach 1:
A single movable vane is introduced to enable dynamic adjustment of the inlet area. The vane rotates about an axis and can be positioned to open or close the inlet opening, allowing the inlet to adapt between supersonic and subsonic flight modes. This minimal dynamic component achieves flight mode adaptability while adding only slight complexity compared to a completely fixed inlet design.
Solution Approach 2:
The movable vane is controlled by a feedback system that automatically adjusts the inlet area based on detected flight conditions. The control system monitors parameters such as Mach number and mass flow requirements, then actuates the vane to the appropriate position without requiring manual intervention. This self-service capability achieves adaptability while minimizing operational complexity.
Data Source
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AI summary
An assembly is provided for an aircraft propulsion system. This aircraft propulsion system assembly includes a nacelle inlet structure (58). The nacelle inlet structure (58) includes an inner inlet opening (64), an outer inlet opening (66) and a rotating structure (72). The rotating structure (72) extends circumferentially about the inner inlet opening (64). The rotating structure (72) is configured to rotate about an axis (76) between a first position and a second position. The rotating structure (72) at least partially closes the outer inlet opening (66) in the first position. The rotating structure (72) at least partially opens the outer inlet opening (66) in the second position.