Gas Turbine Bleed Valve Noise Reduction via Streamlined Struts

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Solution Overview

Problem

Current noise suppression techniques for gas turbine engine bleed valves are bulky, heavy, and reduce mass flow rate, leading to weight issues and inefficiencies.

Innovation Solution

The design incorporates streamlined struts with specific cross-section shapes to prevent flow separation and vortex shedding, coupled with a muffler section featuring a honeycomb flow straightener to reduce noise, while maintaining structural integrity and flow efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional muffler designs with perforated plates are used, then noise suppression is achieved, but the device becomes bulky and heavy

Engineering Contradiction:
Improvenoise suppressionVSAvoidmuffler weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The patent changes the geometric parameters of the struts by using streamlined cross-sections with specific aspect ratios (≥2) or chord-to-thickness ratios (≥2). This parameter optimization reduces flow separation and vortex shedding, thereby suppressing noise without requiring bulky muffler structures, thus reducing weight while maintaining noise suppression effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates a honeycomb structure within the muffler section, which is a porous material configuration. This honeycomb flow straightener suppresses turbulence and noise while occupying minimal space, avoiding the need for heavy traditional perforated plate designs and reducing overall muffler weight.

Inventive Principle:
Principle #31Porous materials

2Object-affected harmful factors

If multiple suppression stages are added to reduce noise, then noise suppression improves, but mass flow rate decreases and valve size increases

Engineering Contradiction:
Improvenoise suppressionVSAvoidmass flow rate
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent optimizes the strut cross-sectional parameters (aspect ratio ≥2 or chord-to-thickness ratio ≥2) to minimize flow disruption. This allows effective noise suppression through reduced vortex shedding while maintaining high mass flow rate, avoiding the need for multiple suppression stages that would restrict flow.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies noise suppression measures locally at the strut level rather than using multiple global suppression stages. The streamlined strut cross-sections are specifically designed to suppress vortex shedding at its source, providing effective noise reduction without the flow restrictions associated with multiple muffler stages.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If streamlined strut cross-sections with specific ratios are used, then flow separation is prevented and vortex shedding is suppressed, but manufacturing complexity increases

Engineering Contradiction:
Improvevortex shedding suppressionVSAvoidstrut manufacturing
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent specifies clear parameter ranges for strut cross-sections (aspect ratio ≥2 or chord-to-thickness ratio ≥2) that balance aerodynamic performance with manufacturability. These standardized parameter guidelines enable streamlined struts to suppress vortex shedding effectively while remaining feasible for conventional manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

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 approach effectively suppresses noise emissions from bleed valves, enhancing engine performance by reducing weight and maintaining mass flow rate, with streamlined struts and honeycomb muffler sections demonstrating significant noise reduction.

Implementation Method 1

struts that have a streamlined cross-section to prevent substantial flow separation and suppress vortex shedding

Methodology Applied
Scientific EffectFlow separation: Flow Separation

Implementation Method 2

struts that have a streamlined cross-section to prevent substantial flow separation and suppress vortex shedding

Methodology Applied
Scientific EffectVortex shedding: Kármán Vortex Street

Implementation Method 3

The muffler section includes a honeycomb flow straightener

Methodology Applied
Scientific EffectFlow straightening: Laminar Flow

Data Source

PatentEP2694791B1Quiet bleed valve for gas turbine engine and method for reducing noise from a bleed valve
Publication Date: 2018.11.28 RGT UNIV OF CALIFORNIA
  • EP2694791B1 patent drawingFigure 1
  • EP2694791B1 patent drawingFigure 2
  • EP2694791B1 patent drawingFigure 3

AI summary

A bleed valve that expels a gas from a compressed region includes a valve section and a muffler section coupled to and located downstream from the valve section. The valve section includes a centerbody and a housing. The centerbody supports a plunger that controls opening and closing of the bleed valve. The centerbody is coupled to the housing by at least one strut disposed substantially radially. The at least one strut may have a cross-section that reduces or suppresses flow separation and vortex shedding from the at least one strut. The muffler section may include a baffle plate and a dome plate. A honeycomb may be installed between the baffle plate and the dome plate. The bleed valve may also include a middle plate on a face of the honeycomb and a conical diverter immediately upstream from the baffle plate. Other embodiments are also described.