Deformable Aeroengine Inlet for Noise Attenuation
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Solution Overview
Problem
Modern turboprop aircraft engines face increased noise challenges due to compressor noise during approach phases, as traditional noise reduction methods are less effective at lower power conditions, necessitating an improved engine inlet system for noise attenuation.
Innovation Solution
The engine inlet system incorporates a variable intake noise attenuation apparatus with deformable walls and acoustic cells that can change shape to reduce noise propagation, featuring a linear actuator and air pressure control to adjust the deformable walls' position and shape within the inlet duct, optimizing noise absorption during critical flight phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional fixed inlet design is used, then manufacturing simplicity is maintained, but noise attenuation capability during approach phase is insufficient
Solution Approach 1:
The inlet system employs deformable walls that can dynamically change shape between undeployed and deployed configurations. These walls are actuated by linear actuators and air pressure control systems, allowing the inlet to adapt its geometry based on flight conditions. During approach phase, the deformable walls deploy to increase noise attenuation capability, while during other phases they remain undeployed to maintain simpler airflow characteristics.
Solution Approach 2:
The system changes physical parameters of the inlet structure by deploying or retracting the deformable walls. This parameter change allows transition between different noise attenuation states without permanently altering the inlet design. The deformable walls can be positioned at different angles and configurations to optimize performance for specific flight conditions, particularly the approach phase.
2Object-affected harmful factors
If deformable walls are deployed to increase acoustic treatment area, then noise propagation is reduced, but airflow efficiency may be compromised
Solution Approach 1:
The deformable walls are dynamically controlled to deploy only when needed for noise attenuation during approach phase. The linear actuators and air pressure control system enable rapid transition between deployed and undeployed states, allowing the inlet to maintain optimal airflow characteristics during most flight phases while providing enhanced noise attenuation when required.
Solution Approach 2:
The deformable walls are deployed periodically during specific flight phases (approach and landing) rather than remaining constantly deployed. This periodic action ensures noise attenuation is provided when most needed while minimizing any potential impact on airflow efficiency during other flight phases where the walls remain retracted.
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
This solution effectively reduces community noise levels during approach and landing operations by increasing the acoustic treatment area within the inlet duct, minimizing noise propagation while maintaining efficient airflow and pressure recovery.
Implementation Method 1
The compressor inlet may comprise a linear actuator for selectively actuating the at least one deformable wall between the undeployed position and the deployed position
Implementation Method 2
The compressor inlet may comprise an air chamber to which the at least one deformable wall is attached and a device for selectively changing air pressure in the air chamber to result in a change of the shape of the at least one deformable wall
Implementation Method 3
a variable intake noise attenuation apparatus with deformable walls and acoustic cells that can change shape to reduce noise propagation
Data Source
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AI summary
An aeroengine has an inlet system (22) which includes a deformable wall (36,38) disposed adjacent a peripheral wall (32,34) of an inlet duct (24) and a plurality of acoustic cells (40) attached to a back side (42) in fluid communication through respective holes (41) in the deformable wall (36,38) with an inlet duct air flow (11). The deformable wall (36,38) selectively forms part of the peripheral wall (32,34) of the inlet duct (24) when in an undeployed position and selectively forms a curved profile projecting into the inlet duct (24) to reduce line-of-sight noise propagation through the inlet duct (24).