Variable Area Nozzle With Inclined Rotation Axis
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Solution Overview
Problem
Current throat area control systems in supersonic vehicles with afterburners face challenges in maintaining angular trailing edges while varying the nozzle throat area, leading to undesirable gaps and complex sealing requirements, making them infeasible for advanced aircraft designs.
Innovation Solution
A variable area mechanism with a movable flow area control surface that rotates about an off-body axis-of-rotation, utilizing a contoured interface surface to expand and retract without opening asymmetric gaps, and a forward flow panel with a slide interface to seal the angular trailing edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanism rotates around an axis perpendicular to the flow to change throat area, then the flow area can be varied, but asymmetric gaps are opened requiring complicated sealing techniques
Solution Approach 1:
The patent changes the rotation axis from a conventional perpendicular-to-flow orientation to an inclined orientation relative to the flow direction. This dimensional change in the rotation axis orientation allows the mechanism to vary throat area while maintaining continuous contact between the movable surface and nozzle walls, eliminating asymmetric gaps and the need for complicated sealing techniques.
Solution Approach 2:
The patent employs asymmetric geometry in the movable flow area control surface and nozzle configuration. The movable surface is designed with specific angular orientations and contoured interface surfaces that asymmetrically match the nozzle geometry, enabling the mechanism to rotate and seal against the nozzle walls without creating gaps, thus simplifying the sealing requirement.
2Reliability
If edges are oriented perpendicular to the airflow, then sealing is simplified, but radar cross section increases reducing survivability
Solution Approach 1:
The patent employs asymmetric geometry in the movable flow area control surface and nozzle configuration. The movable surface is designed with specific angular orientations and contoured interface surfaces that asymmetrically match the nozzle geometry, enabling the mechanism to rotate and seal against the nozzle walls without creating gaps, thus simplifying the sealing requirement.
Solution Approach 2:
The patent changes the orientation parameter of the rotation axis from perpendicular to inclined relative to the flow direction. This parameter change allows the trailing edges to be oriented at angles to the airflow, reducing radar cross section and improving survivability while the contoured interface surfaces ensure continuous sealing contact.
3Object-affected harmful factors
If edges are oriented at an angle to the airflow to reduce radar cross section, then survivability improves, but gaps open requiring very complicated sealing techniques
Solution Approach 1:
The patent changes the rotation axis from a conventional perpendicular-to-flow orientation to an inclined orientation relative to the flow direction. This dimensional change in the rotation axis orientation allows the mechanism to vary throat area while maintaining continuous contact between the movable surface and nozzle walls, eliminating asymmetric gaps and the need for complicated sealing techniques.
Solution Approach 2:
The contoured interface surface acts as an intermediary element between the movable flow area control surface and the nozzle walls. This specially contoured surface ensures continuous contact and sealing during rotation, mediating the interaction between the angled edges and the nozzle structure, thereby eliminating gaps without requiring additional sealing mechanisms.
Data Source
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AI summary
A variable area mechanism and methods are disclosed. A movable surface (608) comprising a contoured interface surface (618) is operable to rotate about an off-body axis-of-rotation (616) such that the movable surface (608) expands from and retracts into an angle notched surface (606).