Thrust Reverser Cascade Flow Stabilizers for Noise Reduction
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Solution Overview
Problem
Existing thrust reverser systems in aircraft propulsion systems generate excessive noise due to gas flow across cascade structures, which amplifies acoustic feedback and increases the noise signature of the aircraft.
Innovation Solution
Incorporation of flow stabilizers, such as cascade walls and vanes, to disrupt and mitigate sound generation by creating smooth transitions and blocking gas flow between neighboring vanes, thereby reducing acoustic excitation and cavity back-volume modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gas flow is redirected through cascade structures in thrust reverser systems, then reverse thrust is produced, but excessive noise is generated due to acoustic feedback amplification
Solution Approach 1:
Flow stabilizers are introduced as intermediary elements between the gas flow source and the cascade structures. These stabilizers modify the flow characteristics before it reaches the vanes, preventing the generation of strong acoustic feedback without compromising the thrust reversal function. The flow stabilizers act as a mediating component that decouples the direct relationship between gas flow redirection and noise generation.
Solution Approach 2:
The flow stabilizers are positioned at specific locations within the cascade structure where flow disturbances initially occur. By applying flow stabilization only at these critical local regions rather than throughout the entire system, the patent achieves noise reduction while maintaining efficient reverse thrust generation in other areas. This localized approach addresses the noise problem without sacrificing overall system performance.
2Ease of operation
If cascade vanes are used to redirect gas flow, then thrust reversal is achieved, but acoustic feedback is amplified increasing noise signature
Solution Approach 1:
Flow stabilizers serve as intermediary components that modify the gas flow characteristics before it interacts with the cascade vanes. By introducing these stabilizing elements, the patent prevents the direct coupling between gas flow redirection and acoustic feedback amplification, thereby reducing noise while preserving thrust reversal capability.
Solution Approach 2:
The flow stabilizers perform preliminary flow conditioning before the gas reaches the cascade vanes. By pre-stabilizing the flow in advance, the system prevents the formation of strong acoustic feedback loops that would otherwise occur during thrust reversal operation, thus reducing noise signature while maintaining operational effectiveness.
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 implementation of flow stabilizers effectively reduces noise by targeting dominant Rossiter modes and preventing sound amplification, leading to a quieter aircraft propulsion system operation.
Implementation Method 1
gas flow across cascade structures, which amplifies acoustic feedback and increases the noise signature of the aircraft
Implementation Method 2
flow stabilizers, such as cascade walls and vanes, to disrupt and mitigate sound generation by creating smooth transitions and blocking gas flow between neighboring vanes
Data Source
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AI summary
An apparatus (20) is provided for an aircraft propulsion system (22). This apparatus (20) includes a thrust reverser cascade (64) extending longitudinally between a cascade forward end (68) and a cascade aft end (70). The thrust reverser cascade (64) extends laterally between a cascade first side (72) and a cascade second side (74). The thrust reverser cascade (64) extends radially between a cascade inner face (76) and a cascade outer face (78). The thrust reverser cascade (64) includes a plurality of vanes (86) and a wall (100). The vanes (86) are arranged in a longitudinally extending array along the cascade inner face (76). The vanes (86) include a first vane (86B) and a second vane (86C). The wall (100) is configured to block gas flow radially through the thrust reverser cascade (64) between the first vane (86B) and the second vane (86C).