CMC Combustor Heat Shield Segmented Design

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Solution Overview

Problem

Existing combustor heat shields in gas turbine engines require cooling to withstand high combustion gas temperatures, which negatively impacts turbine emissions and efficiency, and are difficult to fabricate and assemble due to complex shapes.

Innovation Solution

A contoured ceramic matrix composite (CMC) heat shield with segmented design and collars for attachment to the combustor dome, aligned with fuel-air mixers, which reduces the need for cooling fluid and simplifies assembly by using CMC materials for the heat shield and dome components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional metal heat shields are used to protect the combustor dome, then the dome is protected from high temperatures, but cooling fluid is required which negatively impacts turbine emissions and efficiency

Engineering Contradiction:

Improveprotection of combustor domeVSAvoidturbine emissions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The heat shield is made from ceramic matrix composite (CMC) materials that can withstand high temperatures without requiring cooling fluid. The CMC material provides both thermal protection and structural integrity, eliminating the need for cooling systems that would otherwise increase emissions and reduce efficiency.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The CMC heat shield is designed as a single-piece component that can operate in high-temperature environments without active cooling, effectively replacing the traditional metal heat shield system that required cooling fluid circulation and associated infrastructure.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If traditional metal heat shields with complex shapes are fabricated, then the required thermal protection is achieved, but fabrication and assembly become difficult requiring complex tooling and numerous metal pieces

Engineering Contradiction:

Improvethermal protection capabilityVSAvoidfabrication difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The CMC heat shield is fabricated as a single-piece monolithic structure rather than assembling multiple metal pieces. This segmentation principle is applied in reverse - by eliminating joints and connections, the design simplifies both fabrication and assembly while maintaining the complex contoured shape needed for thermal protection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

CMC materials can be formed into complex contoured shapes during the manufacturing process itself, rather than requiring post-fabrication assembly of multiple pieces. The material's properties allow for direct formation of the required geometry, simplifying both fabrication and assembly operations.

Inventive Principle:

Principle #40Composite materials

3Strength

If cooling fluid is directed against metal heat shields to withstand high temperatures, then the heat shield maintains structural integrity, but turbine performance and efficiency are reduced

Engineering Contradiction:

Improveheat shield structural integrityVSAvoidturbine efficiency

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The CMC heat shield material inherently withstands high temperatures without requiring active cooling, maintaining structural integrity through the material's thermal resistance properties rather than through cooling fluid circulation. This eliminates the performance penalty associated with cooling system requirements.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The heat shield is designed to operate passively in high-temperature environments without requiring ongoing cooling fluid supply infrastructure, effectively removing the efficiency-reducing cooling system while maintaining protective function.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 CMC heat shield effectively protects the combustor dome from high temperatures without the need for cooling fluid, improving turbine performance and efficiency while reducing emissions and simplifying the assembly process with integrated CMC components.

Implementation Method 1

CMC materials can withstand relatively extreme temperatures... heat shields that can withstand increased combustion gas temperatures yet also require less cooling

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS10816199B2Combustor heat shield and attachment features

Publication Date: 2020.10.27 GENERAL ELECTRIC CO

AI summary

Combustor assemblies and combustor heat shields are provided. As one example, a combustor assembly comprises a flow path assembly including an outer wall, an inner wall, and a combustor dome that define a combustion chamber and are formed from a ceramic matrix composite (CMC) material. The combustor dome defines a plurality of dome openings, and a heat shield is positioned between the combustor dome and the combustion chamber that comprises a plurality of heat shield segments. Each heat shield segment defines a heat shield aperture that is aligned with a dome opening, and an aft surface of each segment is concave and a forward surface of each segment is convex. One of a plurality of fuel-air mixers is positioned through each heat shield aperture and dome opening, and one collar of a plurality of collars extends through each heat shield aperture to couple the heat shield to the fuel-air mixer.