Ceramic Airfoil Cooling Circuit for Reduced Compressor Bleed

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Solution Overview

Problem

Gas turbine engines face efficiency challenges due to the need for compressor bleed cooling, which penalizes engine performance by relying on pressure differential, making it difficult to achieve lower volume, increased velocity, and higher temperature bleed while maintaining high pressure and low temperature compressor bleed for effective pressure differential.

Innovation Solution

The development of a ceramic airfoil piece with a core cavity and internal cooling circuit, featuring inlet and outlet holes, flow guides, and dimples to enhance thermal resistance and reduce the need for compressor bleed cooling, by effectively managing thermal stress and distributing cooling air through a complex network of passages and ribs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If compressor bleed cooling is used to cool turbine components, then the temperature resistance of turbine components is improved, but engine efficiency deteriorates due to pressure differential requirements

Engineering Contradiction:
Improvetemperature resistance of turbine componentsVSAvoidengine efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent replaces the mechanical/compression-based cooling system (compressor bleed) with a thermal field-based solution (internal cooling circuits with coolant flow). The cooling function is achieved through thermal convection and conduction within dedicated passages rather than through compressor pressure differentials, thereby substituting a mechanical system with a thermal management system that does not penalize engine performance

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary cooling fluid (coolant) that circulates through internal cooling circuits within the turbine components. This intermediary substance absorbs heat from the turbine components through conduction and convection, acting as a mediator between the hot turbine components and the external cooling system, thereby enabling effective cooling without direct reliance on compressor bleed air

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If compressor bleed volume is reduced to improve engine efficiency, then engine performance is improved, but the ability to provide effective cooling deteriorates

Engineering Contradiction:
Improveengine performanceVSAvoidcooling effectiveness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the cooling function into dedicated internal cooling circuits within turbine components, separate from the compressor bleed system. By dividing the thermal management function into independent cooling passages and circuits, the system can provide reliable cooling through controlled coolant flow without relying on compressor bleed volume, thus maintaining both engine performance and cooling effectiveness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-dimension compressor bleed cooling approach to a multi-dimensional cooling system with internal passages, flow distributors, and multiple cooling zones. This dimensional expansion of the cooling architecture enables effective heat removal through distributed coolant flow paths, ensuring reliable cooling independent of compressor bleed volume

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If compressor bleed temperature is increased to improve engine efficiency, then engine performance is improved, but cooling effectiveness deteriorates

Engineering Contradiction:
Improveengine performanceVSAvoidcooling effectiveness
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent uses a dedicated coolant as an intermediary substance with controlled temperature, separating the cooling function from the hot compressor bleed air. The coolant circulates through internal cooling circuits, absorbing heat from turbine components through thermal conduction and convection, thereby providing effective cooling independent of compressor bleed temperature and enabling engine performance optimization

Inventive Principle:
Principle #24Intermediary (Mediator)

4Loss of energy

If ceramic airfoil piece with internal cooling circuit is implemented, then temperature resistance is improved and compressor bleed cooling is reduced, but device complexity increases

Engineering Contradiction:
Improvecompressor bleed cooling requirementVSAvoidstructure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges the cooling function directly into the turbine component structure by integrating internal cooling circuits within the ceramic airfoil piece. The cooling passages, flow distributors, and thermal management features are combined with the airfoil structure itself, creating a unified component that provides both aerodynamic function and thermal management, thereby reducing overall system complexity despite the advanced features

Inventive Principle:
Principle #5Merging (Combining)

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 temperature resistance of turbine components, reducing the need for compressor bleed cooling and thereby improving engine efficiency by effectively managing thermal stress and distributing cooling air, leading to improved thermodynamic performance.

Implementation Method 1

distributing cooling air through a complex network of passages and ribs

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

distributing cooling air through a complex network of passages and ribs

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

enhance thermal resistance and reduce the need for compressor bleed cooling

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3323997B1Airfoil with ceramic airfoil piece having internal cooling circuit
Publication Date: 2021.06.02 RTX CORP
  • EP3323997B1 patent drawingFigure 1~2A
  • EP3323997B1 patent drawingFigure 2B
  • EP3323997B1 patent drawingFigure 3~4

AI summary

An airfoil includes an airfoil section that has radially inner and outer ends and defines an airfoil profile. The airfoil profile has a leading end, a trailing end, a suction side, and a pressure side. The airfoil section includes a ceramic airfoil piece that defines a portion of the airfoil profile. The ceramic airfoil piece includes an exterior wall that has an internal cooling circuit.