CMC Arc Segment Gap Blocking for Turbine Gas Leakage

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Solution Overview

Problem

Implementing ceramic matrix composite (CMC) materials in gas turbine engines faces challenges due to unique leak paths in uncooled components, as there is no compressor bleed air to limit gas leakage through intersegment gaps in the turbine section.

Innovation Solution

Incorporating CMC arc segments with a CMC strip at the interface to block leak paths, using a low filament count and specific fiber architecture to form a physical barrier that reduces gas leakage, and employing a silicon-containing coating to enhance sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If CMC arc segments are used in the turbine section, then temperature resistance is improved, but gas leakage through intersegment gaps increases

Engineering Contradiction:

Improvetemperature resistanceVSAvoidgas leakage

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

A CMC strip is introduced as an intermediary element at the interface between adjacent CMC arc segments. The strip fills the gap created by the segmented structure and blocks the leak path for hot gas, preventing energy loss while maintaining the temperature resistance benefits of CMC materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The interface structure combines CMC arc segments with a CMC strip to create a composite sealing system. The strip is made of CMC material with specific fiber architecture (low filament count) that provides both structural integrity and flow-blocking capability, maintaining compatibility with the high-temperature environment while sealing the gap.

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If CMC arc segments are used in the turbine section, then component lifetime is improved, but device complexity increases

Engineering Contradiction:

Improvecomponent lifetimeVSAvoiddevice complexity

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The support ring is divided into multiple CMC arc segments that can be manufactured and assembled separately. This segmentation allows for easier fabrication of complex CMC components while extending component lifetime through the use of temperature-resistant materials.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The CMC strip serves as an intermediary element that simplifies the overall design by providing a standardized sealing solution at the interfaces between arc segments, reducing the complexity of creating seamless joints while maintaining component integrity and extended service life.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If a CMC strip is added at the interface, then gas leakage is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improvegas leakageVSAvoidmanufacturing complexity

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The CMC strip is designed as a relatively simple, replaceable component compared to the complex CMC arc segments. While it adds a manufacturing step, the strip itself can be produced using simpler processes and is designed to be replaced if needed, balancing the increase in assembly complexity with ease of individual component manufacturing.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4276285B1CMC arc segment interface gap flow blocker

Publication Date: 2026.01.28 RTX CORP

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AI summary

A gas turbine engine (20) includes a plurality of ceramic matrix composite (CMC) arc segments (62) arranged in a row. There is a leak path (74) through which gas from the engine core gas path (C) can bypass an axial section of the engine core gas path (C). A CMC strip (76) is disposed at the inter-segment interface (71) between CMC arc segments (62) to block the leak path (74) and reduce leakage of the gas.