Compressor Bleed Plenum Projections for Resonance Prevention
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Solution Overview
Problem
Conventional gas turbine engines experience aero-acoustic resonance in the engine bleed plenum, leading to damaging pressure waves and noise, which can cause compressor stall and structural damage.
Innovation Solution
The geometry of the bleed plenum is modified with outwardly extending projections, such as convex surfaces or sound-absorbing materials, to alter the internal volume and geometry, disrupting resonant frequencies and reducing unwanted acoustic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bleed passage releases air into the plenum to prevent compressor stall, then compressor reliability is improved, but aero-acoustic resonance and damaging pressure waves are generated in the plenum
Solution Approach 1:
The patent modifies the plenum geometry by adding outwardly extending projections that extend into the plenum volume. This changes the acoustic parameters of the plenum (volume, surface area, shape) to alter its resonant frequencies, ensuring they do not coincide with excitation frequencies from the bleed passage, thereby preventing resonance while maintaining compressor protection functionality
Solution Approach 2:
The patent converts the potentially harmful resonance phenomenon into a beneficial design feature by deliberately shaping the plenum projections to create anti-resonance effects. The projections are designed to generate pressure waves that counteract and cancel the damaging resonant waves, transforming the acoustic field from harmful to protective
2Object-affected harmful factors
If the plenum geometry is modified with outwardly extending projections to prevent resonance, then aero-acoustic performance is improved, but plenum volume is reduced
Solution Approach 1:
The patent carefully designs the projections to achieve the desired acoustic parameter changes (shape, surface area distribution) while minimizing volume reduction. The projections are optimized in terms of their extension distance, cross-sectional area, and positioning to achieve resonance prevention with minimal impact on plenum volume, balancing acoustic performance with functional capacity
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 modified plenum geometry prevents aero-acoustic resonance, minimizing pressure fluctuations and vibrations, thereby protecting the compressor and reducing noise emissions.
Implementation Method 1
The resonance can be dangerous for the rotating turbomachinery as the generated fluctuating pressure waves can lead to failure. These pressure waves can be damaging to the compressor and other structures.
Implementation Method 2
The outwardly extending projection is in the form of a smooth convex surface and the smooth convex surface extends into the plenum
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A gas turbine engine comprising at least one radially extending bleed passage in fluid communication with at least one generally circumferentially extending plenum. A plenum has an upstream end in fluid communication with a bleed passage and an outlet for releasing air from the plenum. A plenum further comprises a downstream surface defining a downstream closed end of the plenum and the downstream surface of one or more plenum is/are provided with an outwardly extending projection extending into the plenum.