CMC Blade Track with Integral Abradable Layer

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Solution Overview

Problem

Ceramic matrix composites (CMCs) used in gas turbine engines face challenges in maintaining structural integrity at high temperatures while allowing for blade incursion and thermal insulation, as existing materials do not effectively degrade to facilitate blade guidance and insulation simultaneously.

Innovation Solution

A multi-layer CMC blade track is fabricated with a structural layer made of oxide fibers and matrix, and an abradable layer made of different oxide fibers that degrades at operational temperatures, allowing blade incursion and providing thermal insulation by infiltrating both layers with ceramic matrix materials, with the abradable layer having a lower fiber density for easier blade interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single-layer CMC blade track is used, then manufacturing is simpler, but it cannot simultaneously provide structural integrity and blade incursion capability

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddual functionality (structural integrity and blade incursion)

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The blade track is divided into two distinct layers: a structural layer providing mechanical strength and an abradable layer enabling blade incursion. This segmentation allows each layer to be optimized for its specific function while being manufactured as an integrated component through sequential infiltration of the fiber preform.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite ceramic matrix composite materials with different properties in each layer. The structural layer uses fibers oriented for strength, while the abradable layer uses fibers oriented for controlled degradation, creating a multi-functional composite structure that satisfies both requirements simultaneously.

Inventive Principle:

Principle #40Composite materials

2Strength

If the CMC material is made more durable, then structural integrity is improved, but blade incursion capability deteriorates

Engineering Contradiction:

Improvestructural integrityVSAvoidblade incursion capability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

Different regions of the blade track have different material properties: the structural layer has high strength and durability, while the abradable layer has controlled degradation characteristics. This local differentiation of material quality allows the track to be durable where needed while remaining operable where blade contact occurs.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The functional segmentation separates the durability requirement (structural layer) from the blade incursion requirement (abradable layer), allowing each segment to be optimized independently for its specific purpose while maintaining overall system integrity.

Inventive Principle:

Principle #1Segmentation

3Temperature

If the CMC blade track provides thermal insulation, then structural layer protection is improved, but heat resistance requirement becomes more challenging

Engineering Contradiction:

Improvethermal insulation capabilityVSAvoidheat resistance at operational temperatures

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The composite CMC structure with its layered architecture and ceramic matrix provides inherent thermal insulation properties while maintaining heat resistance. The porous preform structure and matrix material composition are selected to optimize both insulation and thermal stability at operational temperatures.

Inventive Principle:

Principle #40Composite materials

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 enables the blade track to maintain structural integrity at high temperatures while facilitating blade incursion and providing thermal insulation, enhancing the operational efficiency and durability of gas turbine engine components.

Implementation Method 1

The abradable layer degrades in strength at temperatures of operation of a gas turbine engine in which the blade track is installed

Methodology Applied

Scientific EffectThermal degradation:

Implementation Method 2

the abradable layer may insulate the structural layer from high operation temperatures inside the gas turbine engine

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS11261750B2CMC blade track with integral abradable

Publication Date: 2022.03.01 ROLLS ROYCE CORP

AI summary

A system and method for forming a ceramic matrix composite blade track is provided. The method may include stacking a plurality of first plies to form a first porous preform layer, the first plies including a plurality of first ceramic fibers. The method may further include stacking a plurality of second plies to form a second porous preform layer, the second plies including a plurality of second ceramic fibers. The method may further include combining the first porous preform layer and the second porous preform layer to form a unified porous preform. The method may further include forming a structural layer by infiltrating the first porous preform with a first ceramic matrix material, and forming an abradable layer by infiltrating the second porous preform with a second ceramic matrix material.