CMC Combustor Panel Attachment Flange Design

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Attaching ceramic matrix composite (CMC) panels to metallic liners in gas turbine engine combustors is challenging due to thermal expansion differences and poor stress loading at attachment points, limiting their use in high-temperature applications.

Innovation Solution

The use of CMC panels with attachment flanges that position the metal-CMC interface away from the hot side, reducing thermal stress and incorporating fastening members with elongate bases and radially extending studs to secure the panels to metallic liners, allowing for thermal regulation and stress distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If CMC panels are attached to metallic liners, then temperature capability and weight reduction are improved, but thermal stress and attachment reliability deteriorate due to thermal expansion differences

Engineering Contradiction:

Improvemaximum operating temperatureVSAvoidattachment reliability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

A metallic transition panel is introduced as an intermediary component between the CMC panel and the metallic liner. This transition panel has a first interface for attaching to the CMC panel and a second interface for attaching to the metallic liner, thereby mediating the thermal expansion differences and reducing thermal stress at the attachment interfaces. The transition panel acts as a buffer that accommodates the differential thermal expansion between the CMC material and the metallic structures.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If CMC panels are attached to metallic liners, then temperature capability is improved, but stress concentration and structural durability worsen at attachment points

Engineering Contradiction:

Improvemaximum operating temperatureVSAvoidstructural durability

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The attachment structure is segmented into multiple distinct components: the CMC panel, the metallic transition panel, and the metallic liner. This segmentation allows each component to be optimized for its specific function and material properties, distributing the mechanical and thermal stresses across multiple interfaces rather than concentrating them at a single attachment point, thereby improving structural durability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the attachment structure are designed with different material properties and geometries to locally address specific stress conditions. The transition panel has different interfaces optimized for different materials: one interface for CMC attachment and another for metallic liner attachment, with each interface having appropriate geometric features and material characteristics to handle the local stress state.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If attachment flanges are positioned on the hot side, then attachment is simplified, but thermal stress increases due to high-temperature exposure

Engineering Contradiction:

Improveattachment simplicityVSAvoidthermal stress

Core Design Contradiction:

Ease of manufactureVSStress or pressure

Solution Approach 1:

Instead of positioning the attachment flange on the hot side of the CMC panel as would be conventional, the attachment flange is inverted to the cold side. This inversion places the attachment interface in a lower temperature region, reducing thermal stress while still achieving secure attachment. The cold side attachment flange is connected to the CMC panel through the transition panel, maintaining structural integrity while avoiding high-temperature exposure at the attachment points.

Inventive Principle:

Principle #13The other way round (Inversion)

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 solution enhances thermal capabilities and structural durability of CMC panels, reducing thermal stress and improving attachment reliability, enabling their use in high-temperature gas turbine engine combustors while maintaining compatibility with existing metallic structures.

Implementation Method 1

This allows the metal-CMC attachment interface to be situated away from the hot, inner side of the panel, which reduces thermal stress on the interface

Methodology Applied

Scientific EffectThermal gradient: Temperature Gradient

Implementation Method 2

incorporating fastening members with elongate bases and radially extending studs to secure the panels to metallic liners, allowing for thermal regulation and stress distribution

Methodology Applied

Scientific EffectStress distribution:

Data Source

PatentEP3623704B1Combustor panel for gas turbine engine

Publication Date: 2021.04.28 RTX CORP

Figure 1
Figure 2
Figure 3~4

AI summary

A combustor panel (68, 168) for use in a gas turbine engine includes a body portion (72) having an outwardly curved edge (82) defining a channel (90) between the body portion (72) and the outwardly curved edge (82). The outwardly curved edge (82) includes a plurality of slots (88). The panel (68, 168) further includes a fastening member (92) having a base (94) disposed within the channel (90) and a plurality of fasteners (96) extending from the base (94) and disposed within the slots (88).