Gas Turbine Pre-Diffuser Strut with Hollow Cavity and Aperture

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Solution Overview

Problem

Existing pre-diffuser struts in gas turbine engines primarily serve structural purposes and lack significant aerodynamic functionality, necessitating an improvement in design to enhance both structural rigidity and aerodynamic efficiency.

Innovation Solution

The design incorporates struts with radially extending apertures and hollow cavities within the pre-diffuser of the inner diffuser case, allowing for secondary cooling airflow and reducing weight while maintaining structural support, featuring a radially-extending wall separating the aperture and hollow cavity, and using a mold for casting with specific wall thicknesses for optimal performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If solid struts are used to maintain structural rigidity of the pre-diffuser, then structural strength is improved, but weight increases

Engineering Contradiction:
Improvestructural rigidityVSAvoidpre-diffuser weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The strut is designed with a hollow internal cavity rather than being completely solid, creating a porous-like structure that reduces weight while maintaining structural integrity. This allows the strut to support the pre-diffuser assembly with reduced material usage.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The strut incorporates multiple functional elements (hollow cavity for weight reduction, aperture for cooling airflow) within a single structural component, creating a composite design that simultaneously addresses weight, structural, and thermal management requirements.

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If strut weight is reduced for better fuel efficiency, then fuel consumption is improved, but structural support capability deteriorates

Engineering Contradiction:
Improvefuel efficiencyVSAvoidstructural support
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The hollow cavity within the strut creates a lightweight structure that reduces overall pre-diffuser weight, directly improving fuel efficiency while the carefully designed cavity dimensions maintain sufficient structural strength.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The strut wall thickness and cavity dimensions are optimized to specific parameters that balance weight reduction with structural support requirements, ensuring the lightweight strut can still bear the necessary loads.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If traditional struts are used without aerodynamic features, then manufacturing simplicity is maintained, but aerodynamic efficiency deteriorates

Engineering Contradiction:
Improvestrut manufacturingVSAvoidaerodynamic efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The strut is designed to perform multiple functions simultaneously: structural support, weight reduction, and aerodynamic flow management. The hollow cavity and aperture features enable cooling airflow passage while the strut maintains its structural role.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The strut incorporates pneumatic flow paths through the hollow cavity and aperture to enable secondary cooling airflow to pass through the pre-diffuser structure, improving thermal management without adding separate cooling components.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Temperature

If struts with cooling airflow passages are added to improve heat dissipation, then thermal management is improved, but device complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidstrut structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling airflow passages are merged into the strut structure itself rather than being separate components. The hollow cavity and aperture are integrated directly into the strut, combining structural and thermal management functions in one element.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The strut serves as both a structural support element and a thermal management component with integrated cooling airflow passages, eliminating the need for separate cooling system components and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design enhances the aerodynamic efficiency and structural stability of the pre-diffuser, reduces weight, and improves fuel efficiency in gas turbine engines by providing a passage for secondary cooling airflow and optimizing strut thickness for balanced support and weight reduction.

Implementation Method 1

the aperture may provide a passage for secondary cooling airflow between a bearing compartment and an aft portion of a compressor section of the gas turbine engine

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

the passage formed by the pre-diffuser may expand in area from an inlet to an outlet of the pre-diffuser, thereby allowing a reduction of the compressed air velocity via area expansion

Methodology Applied
Scientific EffectDiffuser effect:

Data Source

PatentEP3034804B1Pre-diffuser strut for gas turbine engine
Publication Date: 2019.11.20 UNITED TECH CORP
  • EP3034804B1 patent drawingFigure 1
  • EP3034804B1 patent drawingFigure 2
  • EP3034804B1 patent drawingFigure 3

AI summary

A pre-diffuser (60) of an inner diffuser case (54) of a gas turbine engine (10) may comprise an annular outer wall (64) and an annular inner wall (66) radially inside of the annular outer wall (64) to define a passage (61) for primary airflow (56) therebetween. The pre-diffuser (60) may further comprise at least one strut (72) extending radially between the annular inner wall (66) and the annular outer wall (64) and at least one aperture (78) formed in the strut (72) that extends radially through the strut (72), the annular inner wall (66), and the annular outer wall (64). The pre-diffuser (60) may further comprise at least one hollow cavity (84) formed in the strut (72), and the hollow cavity (84) may be separate from the aperture (78).