CMC Component Cooling Air Compartmentalization via Rope Seal

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Solution Overview

Problem

Existing gas turbine engines face inefficiencies in cooling high-temperature turbine components due to single-wall cooling configurations, which do not effectively utilize cooling air to manage thermal stresses and pressure distribution across CMC airfoil components.

Innovation Solution

The implementation of a compartmentalization method using a rope seal between CMC and metallic components, with grooves for compression, to control airflow and distribute cooling air across multiple sections, thereby optimizing cooling flow and reducing thermal stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If single-wall cooling configurations are used in turbine components, then the structure is simpler and easier to manufacture, but the cooling air distribution is insufficient and thermal stress management is ineffective

Engineering Contradiction:

Improvethermal stress managementVSAvoidcooling configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cooling air flow is divided into multiple compartments using rope seals positioned at interfaces between CMC and metallic components. This segmentation allows independent control of cooling air in different sections of the turbine component, enabling optimized thermal stress management in each compartment while maintaining overall structural integrity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different compartments of cooling air are directed to specific locations within the turbine component based on local thermal requirements. The rope seal configuration enables tailored cooling air distribution to high-stress areas, providing localized thermal management rather than uniform cooling across the entire component

Inventive Principle:

Principle #3Local quality

2Reliability

If more cooling air is extracted from the compressor to cool turbine components, then the thermal management improves, but the engine operating efficiency decreases

Engineering Contradiction:

Improvecomponent lifeVSAvoidengine efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The compartmentalized cooling system uses cooling air more efficiently by directing it precisely where needed rather than using excessive amounts. The rope seal configuration enables effective cooling with optimized air flow distribution, reducing the total quantity of cooling air required while maintaining component life and thermal management

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If rope seals are compressed between CMC and metallic components, then the sealing and compartmentalization improve, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvesealing effectivenessVSAvoidgroove dimensions

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The rope seal design utilizes compression to achieve sealing, transforming the fitting tolerance requirements into a compression-based sealing mechanism. The grooves are designed to compress the rope seal material between CMC and metallic components, where the compression force creates effective sealing even with moderate manufacturing tolerances, rather than relying on precision interference fits

Inventive Principle:

Principle #35Parameter changes

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 approach enhances the distribution and control of cooling air, minimizing thermal stress buildup and improving the thermal endurance of CMC components, while maintaining structural integrity and engine efficiency.

Implementation Method 1

compartmentalizing sections of the airflow while distributing CMC airfoil load across multiple locations

Methodology Applied

Scientific EffectFluid flow control:

Implementation Method 2

grooves for compression

Methodology Applied

Scientific EffectMechanical compression: Compression

Implementation Method 3

controlling the flow of air via an improved component through compartmentalizing sections of the airflow

Methodology Applied

Scientific EffectConvection cooling: Convection

Implementation Method 4

minimizing thermal stress buildup

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS10502072B2Compartmentalization of cooling air flow in a structure comprising a CMC component

Publication Date: 2019.12.10 ROLLS ROYCE CORP

AI summary

A structure in a gas turbine engine comprises a spar and a CMC component adjoining the spar and separated from the spar by a cavity supplied by cooling air. At least one rope seal is installed in the cavity within a groove made in the spar to thus compartmentalize the cavity and control the flow of cooling air.