Variable Bleed Valve Strut for Acoustic Resonance Dampening
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Solution Overview
Problem
In gas turbine engines, the rotor blade tips of the low-pressure compressor cause turbulent airflow that generates acoustic resonance in the variable bleed valve cavity, leading to negative effects such as crack formation and mechanical faults in other components.
Innovation Solution
The implementation of struts with variably sized holes in the variable bleed valve cavities, arranged in specific patterns to dampen acoustic resonance and reduce the likelihood of resonance-induced vibrations and mechanical failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a variable bleed valve cavity is used in the low-pressure compressor, then the valve can control airflow and improve compressor stability, but the cavity generates acoustic resonance due to turbulent airflow from rotor blade tips, leading to crack formation and mechanical faults
Solution Approach 1:
A strut is introduced as an intermediary component within the bleed valve cavity. This strut acts as a mediator between the turbulent airflow from rotor blade tips and the cavity structure, disrupting the shear layers that generate acoustic resonance while maintaining the cavity's airflow control function
Solution Approach 2:
The strut is designed with a porous structure containing multiple holes or cavities. This porous configuration allows the strut to interact with turbulent airflow, dissipating acoustic energy and dampening resonance through the porous structure while still permitting controlled airflow through the bleed valve cavity
2Ease of manufacture
If the bleed valve cavity is left open or unmodified, then manufacturing is simpler, but acoustic resonance occurs causing crack formation and mechanical failures in compressor components
Solution Approach 1:
The strut is segmented into multiple sections with varying hole sizes and distributions. This segmentation allows the structure to effectively dampen a broader range of acoustic frequencies while maintaining manufacturing feasibility through modular construction or standardized porous material fabrication
3Stability of the object's composition
If struts with holes are added to the bleed valve cavity, then acoustic resonance is dampened and aerodynamic stability is improved, but the device complexity increases
Solution Approach 1:
The strut employs a porous structure with multiple holes that can be manufactured using standardized processes. This approach achieves aerodynamic stability and resonance dampening without requiring complex custom fabrication, as porous materials and hole patterns can be produced through established manufacturing techniques
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 effectively reduces the occurrence of acoustic resonance and associated mechanical issues, enhancing the stability and longevity of low-pressure compressor components by disrupting shear layers and acting as Helmholtz resonators to dampen resonant acoustic responses.
Implementation Method 1
acting as Helmholtz resonators to dampen resonant acoustic responses
Implementation Method 2
disrupting shear layers and acting as Helmholtz resonators to dampen resonant acoustic responses
Data Source
AI summary
Variable bleed valves with struts for aerodynamic stability are described. An apparatus described herein includes a variable bleed valve port, and a strut disposed within the variable bleed valve port, the strut defining a plane and a plurality of holes disposed perpendicularly to the plane, the plurality of holes disposed in a pattern to dampen an acoustic response associated with the variable bleed valve port.