Variable Area Nozzle Assembly for Aircraft Propulsion
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Solution Overview
Problem
Existing exhaust nozzle assemblies for aircraft propulsion systems lack the ability to efficiently manage and control the flow of both primary and secondary gas streams, leading to suboptimal performance and potential cooling issues.
Innovation Solution
A variable area nozzle assembly comprising a center plug, an outer nozzle, and an inner nozzle, with the inner nozzle being axially translatable to adjust the cross-sectional area of the primary duct and control the fluid communication of secondary gas streams through apertures, facilitated by a linear actuation system and a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed nozzle assembly is used, then the structure is simple and easy to manufacture, but the ability to control and manage primary and secondary gas stream flows is insufficient
Solution Approach 1:
The inner nozzle is made axially translatable between a first axial position and a second axial position, transforming the fixed nozzle structure into a dynamic one. This allows the cross-sectional area of the primary duct and the fluid communication of secondary gas streams to be adjusted, enabling precise control of gas stream flows while maintaining a relatively simple overall structure.
Solution Approach 2:
The nozzle assembly is segmented into distinct components: center plug, outer nozzle, and inner nozzle. The inner nozzle can be independently actuated axially, allowing separate control of primary and secondary gas streams. This segmentation enables sophisticated flow control functionality while keeping each individual component relatively simple to manufacture.
2Productivity
If the inner nozzle is positioned to increase primary duct cross-sectional area, then primary gas stream flow is improved, but secondary gas stream control and cooling capability is reduced
Solution Approach 1:
The axial position of the inner nozzle is dynamically adjustable between first and second positions. In the first axial position, the primary duct has a larger cross-sectional area for improved primary gas stream flow. In the second axial position, the apertures are connected to the gap to enable secondary gas stream flow for cooling. This dynamic repositioning allows the system to optimize for either productivity or reliability as needed.
Solution Approach 2:
The cross-sectional area of the primary duct and the fluid communication status of the apertures are changed by axially translating the inner nozzle. This parameter change enables the system to switch between different operational modes: one optimized for primary gas stream flow (larger area) and another optimized for cooling capability (apertures open to gap).
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
The solution allows for precise control of both primary and secondary gas stream flows, enhancing performance and providing cooling benefits during various operating conditions.
Implementation Method 1
The center plug includes a plug body and a seal. The seal extends circumferentially about the plug body.
Implementation Method 2
The inner nozzle body is axially translatable between and to a first axial position and a second axial position relative to the axis. In the first axial position, the primary duct has a first cross-sectional area at the exit plane and the plurality of apertures are isolated from the gap by the seal. In the second axial position, the primary duct has a second cross-sectional area at the exit plane, the second cross-sectional area is less than the first cross-sectional area, and the plurality of apertures are connected in fluid communication with the gap to direct a secondary gas stream from the secondary duct and into the gap.
Data Source
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AI summary
A variable area nozzle assembly (96) includes a fixed center plug (104), a fixed outer nozzle (108), and an inner nozzle (106). The fixed center plug (104) includes a seal (116). The inner nozzle (106) is disposed between the fixed center plug (104) and the fixed outer nozzle (108) and includes an inner nozzle body (126) that forms a primary duct (148) between the inner nozzle (106) and the fixed outer nozzle (108). The inner nozzle body (126) forms a secondary duct (128) and a gap (142) that is a nozzle outlet of the secondary duct (128). The secondary duct (128) is disposed between the inner nozzle body (126) and the fixed center plug (104) upstream of the seal (116). The inner nozzle body (126) forms a plurality of apertures (144). The inner nozzle body (126) is translatable between a first position and a second position. In the first position, the primary duct (148) has a first cross-sectional area and the plurality of apertures (144) are isolated from the gap (142) by the seal (116). In the second position, the primary duct (148) has a second cross-sectional area and the plurality of apertures (144) are connected in fluid communication with the gap (142).