Gas Turbine Blade Neck Transition Ribs for Thermal Stress Management

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Solution Overview

Problem

Gas turbine engine blades face challenges in designing efficient cooling systems due to differing thermal expansion requirements between airfoil and attachment ribs, which affects the structural integrity and cooling airflow effectiveness.

Innovation Solution

The design incorporates a set of intersecting ribs with varying cross-sectional geometries transitioning from an airfoil to an attachment section, featuring distinct radial airfoil and attachment cross-sectional geometries, which includes multiple ribs and cavities to manage thermal expansion and provide efficient cooling airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If ribs are designed with flexible structure for airfoil thermal expansion, then thermal flexibility is improved, but structural stiffness deteriorates

Engineering Contradiction:
Improvethermal flexibilityVSAvoidstructural stiffness
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The rib structure implements different geometric configurations in different regions: airfoil-section ribs have a first geometry optimized for thermal expansion accommodation, while attachment-section ribs have a second geometry optimized for structural stiffness. This local differentiation allows each region to have the quality it needs without compromising the other region's requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The rib system is segmented into multiple distinct rib structures (airfoil-section ribs and attachment-section ribs) with different geometries. This segmentation allows the cooling system to be divided into functional zones where each segment can be independently optimized for its specific operational requirements.

Inventive Principle:
Principle #1Segmentation

2Strength

If ribs are designed with stiff structure for attachment to prevent crushing, then structural stiffness is improved, but thermal flexibility deteriorates

Engineering Contradiction:
Improvestructural stiffnessVSAvoidthermal flexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The attachment-section ribs are specifically designed with a second geometry that provides enhanced structural stiffness and crushing resistance where the attachment connects to the disk. This localized stiffening ensures attachment integrity while the airfoil-section ribs maintain their flexible geometry for thermal expansion accommodation.

Inventive Principle:
Principle #3Local quality

3Reliability

If cooling airflow is provided through internal cavities, then cooling efficiency is improved, but structural complexity deteriorates

Engineering Contradiction:
Improvecooling efficiencyVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The rib structures serve dual functions: they provide structural support for the blade while simultaneously forming the boundaries of internal cooling cavities. By merging the structural and cooling functions into a single integrated component, the design achieves effective cooling without adding separate complex cooling systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooling system is segmented into multiple internal cavities formed by the rib structures, allowing cooling airflow to be distributed through distinct pathways. This segmentation of the cooling flow enables efficient heat removal while the cavities are created as a byproduct of the rib geometry rather than requiring additional complex components.

Inventive Principle:
Principle #1Segmentation

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 structural stiffness of the attachment section while allowing for thermal flexibility of the airfoil section, improving the overall cooling efficiency and part life of the blades by segregating cooling flows and reducing stress.

Implementation Method 1

Because the outer walls are exposed to relatively hot air, they may experience greater thermal expansion than the internal ribs or walls.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3954863A1Blade neck transition
Publication Date: 2022.02.16 RTX CORP
  • EP3954863A1 patent drawingFigure 1
  • EP3954863A1 patent drawingFigure 2
  • EP3954863A1 patent drawingFigure 3~4B

AI summary

A blade for use with a gas turbine engine includes an attachment (140) and an airfoil (120). The airfoil (120) further includes a suction side wall (202) configured to be exposed to less pressure than the pressure side wall (200) during operation of the gas turbine engine. The blade also includes a plurality of intersecting ribs (210, 212, 410, 411, 412) transitioning from an airfoil cross sectional geometry (400) to an attachment cross section geometry (600).