Segmented Propulsor Cowl Assembly for Wide Nozzle Area and Flutter Resistance
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Solution Overview
Problem
Existing gas turbine engines face challenges in achieving a wide range of nozzle areas without increasing component size or susceptibility to vibrations such as flutter, particularly in designs with fixed pitch fans.
Innovation Solution
A cowl assembly with multiple moveable components that allow for independent or sequential movement, creating multiple aerodynamic slots to vary nozzle area efficiently, minimizing flutter through optimized stiffness and displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a single moveable cowl component is used to vary nozzle area, then the device complexity is reduced, but the nozzle area range is limited and component size must increase to achieve sufficient area variation
Solution Approach 1:
The cowl assembly is divided into multiple independent moveable components (first moveable cowl component and second moveable cowl component) that can move relative to the fixed cowl and each other. This segmentation allows each component to contribute to nozzle area variation independently, achieving a wider nozzle area range without requiring any single component to be excessively large or complex.
Solution Approach 2:
The cowl components are designed to be moveable rather than fixed, allowing dynamic adjustment of the nozzle area. The first and second moveable cowl components can move in the downstream direction relative to the fixed cowl and each other, enabling continuous variation of the nozzle area to optimize performance across different operating conditions.
2Area of moving object
If cowl component size is increased to achieve wider nozzle area range, then the nozzle area range improves, but weight increases and susceptibility to vibrations such as flutter worsens
Solution Approach 1:
By segmenting the cowl assembly into multiple smaller moveable components rather than using a single large moveable component, the patent achieves the required nozzle area range while keeping individual component sizes and weights reduced. The combined movement of multiple smaller components provides the same or greater area variation as a single large component would require.
Solution Approach 2:
The patent utilizes movement in the downstream direction in addition to radial movement, adding another dimension of adjustment. This multi-dimensional movement capability allows the cowl components to achieve greater nozzle area variation without increasing component size, as the area control is distributed across multiple movement degrees of freedom.
3Area of moving object
If cowl component size is increased to achieve wider nozzle area range, then the nozzle area range improves, but susceptibility to vibrations such as flutter worsens
Solution Approach 1:
Dividing the cowl assembly into multiple smaller moveable components reduces the size of each individual component, thereby improving stiffness and reducing susceptibility to flutter and vibrations. Each smaller component has higher structural rigidity relative to its size, making the overall system more stable and resistant to aerodynamic instabilities while still achieving the required nozzle area range through coordinated movement.
4Productivity
If multiple moveable cowl components are used to increase nozzle area range, then the nozzle area range and productivity improve, but device complexity increases
Solution Approach 1:
The cowl assembly is segmented into multiple moveable components that can be independently controlled, allowing for more efficient and rapid adjustment of the nozzle area. This segmentation enables finer control resolution and faster response to changing operating conditions, improving productivity despite the increased number of components.
Solution Approach 2:
The dynamic capability of multiple moveable components allows for rapid and flexible adjustment of the nozzle area in response to changing flight conditions. The system can quickly transition between different area configurations by moving the first and second moveable cowl components independently, enhancing the overall responsiveness and efficiency of the propulsion system.
Data Source
AI summary
A propulsor is provided having a power source; a fan section coupled to the power source and configured to provide thrust opposite a downstream direction; and a cowl assembly at least partially enclosing the power source and the fan section, the cowl assembly including: a forward cowl component; a first aft cowl component disposed in the downstream direction relative to the forward cowl component and movable to vary a first aft cowl displacement from the forward cowl component in the downstream direction; and a second aft cowl component disposed in the downstream direction relative to the first aft cowl component and movable to vary a second aft cowl intermediate displacement from the first aft cowl component.