Gas Turbine Airfoil Triangular Tip Shelf Cooling

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Solution Overview

Problem

Gas turbine engine components in hot sections face increased stress and wear due to high gas path temperatures and pressures, requiring effective cooling to prevent damage while maintaining efficiency.

Innovation Solution

The design incorporates airfoils with improved cooling configurations, including cooling holes and passages, and specific geometries such as squealer pockets and triangular tip shelves to reduce thermal fatigue and fluid leakage, utilizing high-strength materials and coatings to enhance cooling efficiency and service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cooling holes and passages are added to the airfoil, then cooling efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The airfoil is divided into multiple functional zones with different cooling strategies: tip region with squealer pocket and tip shelf, mid-span region with cooling holes, and root region with platform cooling. This segmentation allows targeted cooling where needed while simplifying other areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling structure employs nested geometry where the tip shelf is positioned within the squealer pocket, and cooling holes are integrated into the airfoil body structure. This nesting reduces overall complexity by combining multiple cooling functions into integrated features.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Temperature

If cooling fluid flow is increased, then cooling effect is improved, but engine efficiency decreases

Engineering Contradiction:
Improvecooling effectVSAvoidengine efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

Cooling resources are distributed non-uniformly across the airfoil surface, with higher cooling density at the tip region (squealer pocket and tip shelf) where thermal loads are highest, and reduced cooling in mid-span and root regions. This local quality approach optimizes cooling effectiveness while minimizing cooling fluid consumption and associated efficiency losses.

Inventive Principle:
Principle #3Local quality

3Loss of energy

If tip shelf and squealer pocket geometry are optimized, then fluid leakage is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvefluid leakageVSAvoidmanufacturing precision
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The tip shelf and squealer pocket incorporate curved and tapered geometries rather than sharp corners, which naturally guide fluid flow and reduce leakage while being more tolerant of manufacturing variations. The curved surfaces distribute stress more evenly and are easier to manufacture with standard tolerances.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 thermal effects and increases the service life of airfoil components by providing uniform cooling and minimizing heat transfer, while reducing the cooling fluid flow requirements, thus maintaining engine efficiency.

Implementation Method 1

cooling holes and passages

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

heat transfer

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

minimizing heat transfer and fluid leakage

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP2825733B1Airfoil and corresponding rotor blade for a gas turbine engine
Publication Date: 2020.09.23 RTX CORP
  • EP2825733B1 patent drawingFigure 1
  • EP2825733B1 patent drawingFigure 2A
  • EP2825733B1 patent drawingFigure 2B

AI summary

An airfoil includes a leading edge, a trailing edge, a suction surface, a pressure surface, and a tip shelf. The suction surface and the pressure surface both extend axially to connect the leading edge to the trailing edge. The suction surface and the pressure surface both extend radially from a root section of the airfoil a tip section of the airfoil. The tip shelf is formed along the tip section, and includes a triangular pocket.