Y-Weave CMC Flange Cooling for Blade Outer Air Seal Stress Relief

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Solution Overview

Problem

CMC components with flanges, such as blade outer air seals, face challenges in cooling due to increased material thickness under flanges, leading to higher thermal gradients and thermal stresses, which existing manufacturing methods fail to adequately address.

Innovation Solution

Introduce cooling cavities beneath flanges, such as T-shaped flanges, by forming a triangular-shaped cooling channel using a Y-weave of ceramic fiber plies, with inlet and outlet passages for cooling fluid, during the layup process or post-densification, to facilitate effective cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If CMC components have flanges with increased material thickness, then structural strength is improved, but cooling efficiency deteriorates and thermal gradients increase

Engineering Contradiction:
Improvestructural strengthVSAvoidthermal gradient
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The flange structure is segmented into multiple regions with different thicknesses. The base flange has a first thickness and includes a recess portion with a second thickness that is less than the first thickness. This segmentation allows the main flange body to maintain structural strength while the recess portion reduces material thickness to improve cooling efficiency and reduce thermal gradients in critical cooling areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the flange structure have different material thicknesses tailored to local requirements. The main flange body maintains greater thickness for structural strength, while the recess portion has reduced thickness to improve cooling efficiency. This local variation in thickness optimizes both structural integrity and thermal management performance in different regions of the component.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If CMC components have increased material thickness under flanges, then structural integrity is improved, but cooling capability deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidcooling capability
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The flange is divided into a main body portion with greater thickness for structural integrity and a recess portion with reduced thickness for improved cooling capability. This segmentation allows the component to simultaneously achieve both structural stability and enhanced cooling performance by placing different thickness characteristics in different spatial locations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flange structure incorporates a recess portion that creates a three-dimensional configuration rather than a uniform flat structure. By introducing this vertical dimension variation (the recess), the design achieves both structural integrity from the main body and improved cooling capability from the reduced thickness area, effectively using spatial dimensionality to resolve the contradiction.

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

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

Reduces thermal gradients and thermal stresses by enhancing cooling efficiency, thereby prolonging the operational lifespan of CMC components.

Implementation Method 1

cooling cavities beneath flanges, such as T-shaped flanges, by forming a triangular-shaped cooling channel using a Y-weave of ceramic fiber plies, with inlet and outlet passages for cooling fluid

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP4696869A1Ceramic matrix composite component, blade outer air seal assembly, method of forming a ceramic matrix composite component and gas turbine engine
Publication Date: 2026.02.18 RTX CORP
  • EP4696869A1 patent drawingFigure 1
  • EP4696869A1 patent drawingFigure 2~3
  • EP4696869A1 patent drawingFigure 4

AI summary

A method is described for introducing cooling cavities (140) into CMC components (100) beneath flanges such as T-shaped flanges within the CMC components (100). During layup, preform is made having flanges formed from a Y-shaped weave in which plies of woven ceramic fiber tows form a radial flange section (120) extending from a base of the preform and two bifurcated arms (130, 135). The plies of the two bifurcated arms (130, 135) and plies of the base form a cooling cavity (140) having a triangular cross section beneath the flange. Cooling fluid inlet passages (150; 160) are provided to permit cooling fluid to enter the cooling cavity (140) and thereby cool the internal region of the CMC component (100) to reduce formation of thermal stresses.