Keystoned Blade Track Segments for Gas Turbine Engines

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Solution Overview

Problem

Gas turbine engines face challenges in manufacturing large, full hoop ceramic-matrix composite (CMC) blade tracks due to difficulties in processing large diameter, thin walled parts without distortion or out of roundness, and existing solutions require costly investments in new equipment and processes.

Innovation Solution

The use of ceramic-matrix composite blade track segments keystoned together with a composite-lock structure, where reinforcement fibers are suspended in ceramic-matrix material to form a radially inward force, maintaining the ring shape and eliminating gaps between segments, thereby reducing leakage and improving aerodynamics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a large diameter full hoop CMC blade track is manufactured as a single piece, then the blade track provides continuous coverage and structural integrity, but manufacturing becomes extremely difficult with distortion and out of roundness issues

Engineering Contradiction:

Improveblade track roundness and shape accuracyVSAvoiddifficulty of processing large diameter thin walled parts

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The blade track is divided into multiple segments that can be manufactured separately using conventional processing methods. Each segment is easier to manufacture with proper dimensional control, and the segments are subsequently assembled using composite-lock structures with reinforcement fibers that provide radial inward force to maintain the complete ring shape and eliminate gaps between segments.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If new equipment and processes are invested in to manufacture full hoop CMC blade tracks, then manufacturing capability is improved, but manufacturing costs increase significantly

Engineering Contradiction:

Improvemanufacturing capability for full hoop CMC blade tracksVSAvoidcostly investments in new equipment and processes

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

By segmenting the blade track into multiple smaller parts, the invention enables manufacturing using existing, conventional equipment and processes rather than requiring new, expensive specialized equipment. The segments are assembled using composite-lock structures that integrate reinforcement fibers suspended in ceramic-matrix material to provide the necessary radial inward force.

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If blade track segments are used with gaps between them, then manufacturing and assembly is simplified, but leakage increases and aerodynamic performance deteriorates

Engineering Contradiction:

Improveease of assembling blade track segmentsVSAvoidgas leakage between blade track segments

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The composite-lock structures use reinforcement fibers suspended in ceramic-matrix material to create a composite structure that provides radial inward force. This composite approach enables the segments to be tightly joined without gaps, eliminating leakage paths while maintaining the segmented manufacturing advantage. The fiber reinforcement provides the necessary mechanical properties to maintain segment positioning and eliminate gaps.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS11274567B2Keystoned blade track

Publication Date: 2022.03.15 ROLLS ROYCE NORTH AMERICAN TECHNOLOGIES INC

AI summary

A blade track for a gas turbine engine includes a plurality of blade track segments. The blade track segments are arranged circumferentially around a central axis to form the blade track.