Airfoil Leading Edge Cooling Cavity Design

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Solution Overview

Problem

Current airfoil designs for gas turbine engines face challenges in efficiently cooling the leading edge, particularly in maintaining optimal temperature distribution and structural robustness, especially at the tip where foreign object damage is a concern, due to limitations in cooling cavity orientation and thickness.

Innovation Solution

The airfoil design incorporates a first transitioning leading edge cavity for film cooling at the tip and a second transitioning leading edge cavity with an impingement portion that shields the first cavity, providing a temperature gradient and structural robustness by transitioning from a skin core to an impingement cavity configuration, with varying thicknesses to balance cooling efficiency and damage tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a single leading edge cavity configuration is used, then the structure is simpler, but cooling efficiency and temperature distribution are insufficient

Engineering Contradiction:
Improvetemperature distributionVSAvoidcavity configuration
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The leading edge cooling system is divided into two separate cavities: a first transitioning leading edge cavity and a second transitioning leading edge cavity. Each cavity serves a specific cooling function and can be independently configured, allowing optimized temperature distribution without requiring a single complex cavity design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each cavity is designed with specific local characteristics - the first cavity has a first transitioning configuration while the second cavity has a second transitioning configuration. This allows different regions of the leading edge to receive appropriately tailored cooling, improving overall temperature distribution efficiency.

Inventive Principle:
Principle #3Local quality

2Strength

If wall thickness is increased at the tip for structural robustness, then damage resistance improves, but cooling efficiency decreases

Engineering Contradiction:
Improvedamage resistanceVSAvoidcooling efficiency
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The cooling system is segmented into two cavities that can be positioned at different locations and configured with different geometries. This segmentation allows the cooling function to be maintained even when wall thickness is increased for structural robustness, as the cavities can be optimized to work with the thicker wall configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cavity configurations are designed to transition in specific ways - the first cavity transitions in one manner while the second cavity transitions differently. These parameter changes in cavity geometry allow the system to adapt to varying wall thickness requirements while maintaining cooling efficiency.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If the second cavity shields the first cavity, then temperature control is improved, but the cooling system becomes more complex

Engineering Contradiction:
Improvetemperature controlVSAvoidcavity arrangement
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The second transitioning leading edge cavity is positioned to shield a portion of the first transitioning leading edge cavity. This nested arrangement allows the second cavity to protect the first cavity from direct hot gas exposure, improving temperature control through a hierarchical cavity structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The shielding arrangement provides localized protection - the second cavity shields a portion of the first cavity rather than the entire structure. This selective shielding improves temperature control in critical areas while maintaining overall system simplicity.

Inventive Principle:
Principle #3Local quality

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 cooling efficiency while maintaining structural integrity by maintaining relatively cool temperatures in the first transitioning leading edge cavity and providing robustness through impingement and film cooling, allowing for increased wall thickness at the tip, thus improving part life and thrust-specific fuel consumption.

Implementation Method 1

The second transitioning leading edge cavity comprises a suction side portion and an impingement portion proximate the root, wherein the impingement portion of the second transitioning leading edge cavity shields the first transitioning leading edge cavity such that the temperature of the air within the first transitioning leading edge cavity is relatively cool as compared to the air within the second transitioning leading edge cavity at the root

Methodology Applied
Scientific EffectThermal shielding: Thermal Insulation

Implementation Method 2

the first transitioning leading edge cavity forms a film cooling cavity along the leading edge at the tip of the airfoil body

Methodology Applied
Scientific EffectFilm cooling: Convection

Implementation Method 3

The second transitioning leading edge cavity comprises a suction side portion and an impingement portion proximate the root

Methodology Applied
Scientific EffectImpingement cooling: Convection

Data Source

PatentEP3567218B1Airfoil having improved leading edge cooling scheme and damage resistance
Publication Date: 2022.08.03 RTX CORP
  • EP3567218B1 patent drawingFigure 1
  • EP3567218B1 patent drawingFigure 2
  • EP3567218B1 patent drawingFigure 3A~3B

AI summary

Airfoil for a gas turbine including a body (402) extending between leading (412) and trailing edges (414) in an axial direction, between pressure (416) and suction sides (418) in a circumferential direction, and between a root (406) and tip (408) in a radial direction. A first transitioning leading edge cavity (422) is located adjacent one of the sides proximate the root of the body and transitions axially toward the leading edge as the first transitioning leading edge cavity extends radially toward the tip. A second transitioning leading edge cavity (424) is adjacent the other side and adjacent the leading edge proximate the root of the body and transitions axially toward the trailing edge as the second transitioning leading edge cavity extends radially toward the tip. A portion of the second transitioning leading edge cavity shields a portion of the first transitioning leading edge cavity proximate the root of the body.