Blade Outer Air Seal Support Axial Force Redirection

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Solution Overview

Problem

Existing blade outer air seal components in gas turbine engines, made from high thermal-resistance, low-toughness materials like ceramics, are susceptible to damage from axial forces and thermal stresses, leading to potential failure under operational conditions.

Innovation Solution

A blade outer air seal support system comprising interconnected arc segments with a dynamic seal and cooling features, where axially aligned forces are redirected radially through an interface feature, and a cooling system using impingement cooling holes to manage thermal loads, utilizing materials like monolithic ceramics or ceramic matrix composites.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If high thermal-resistance, low-toughness materials like ceramics are used for blade outer air seal, then thermal resistance is improved, but susceptibility to damage from axial forces and thermal stresses worsens

Engineering Contradiction:
Improvethermal resistanceVSAvoidsusceptibility to damage from axial forces and thermal stresses
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The blade outer air seal is divided into multiple arc segments that can be independently supported and cooled. Each segment is mounted on a support structure with its own cooling passages, allowing localized thermal management and reducing the overall thermal load on any single ceramic component, thereby improving reliability while maintaining thermal resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A support structure made of more toughness-resistant material is introduced as an intermediary between the ceramic blade outer air seal and the engine environment. This support structure absorbs and redistributes axial forces and thermal stresses, protecting the fragile ceramic seal from direct mechanical damage while allowing the ceramic to maintain its thermal resistance properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If ceramic materials are used for blade outer air seal, then thermal resistance is improved, but toughness worsens

Engineering Contradiction:
Improvethermal resistanceVSAvoidtoughness
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The ceramic seal is segmented into multiple smaller arc segments rather than one large continuous component. This segmentation reduces the size of individual ceramic pieces, making them less susceptible to thermal shock and mechanical damage, while the overall seal functionality is maintained through the arrangement of multiple segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blade outer air seal system uses a composite construction where ceramic materials provide thermal resistance and are combined with support structures made of more toughness-resistant materials. This composite approach allows the system to simultaneously achieve high thermal resistance and adequate toughness by leveraging the complementary properties of different materials.

Inventive Principle:
Principle #40Composite materials

3Reliability

If axial forces are applied to blade outer air seal, then sealing function is maintained, but structural integrity worsens due to damage susceptibility

Engineering Contradiction:
Improvesealing functionVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

A support structure serves as an intermediary that bears the axial forces while the ceramic blade outer air seal maintains its sealing function. The support structure is designed to withstand and redistribute axial loads, preventing direct transmission of these forces to the ceramic seal, thereby preserving both the sealing function and structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The support structure redirects axial forces from the axial direction to radial directions through its geometric configuration. By changing the force transmission path from one dimension (axial) to another (radial), the structure prevents direct axial loading of the ceramic seal while maintaining the sealing function through radial support and positioning.

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

The solution effectively redirects axial forces, minimizing damage and maintaining the structural integrity of the blade outer air seal while actively cooling the components to prevent thermal overload, thus enhancing the durability and performance of the gas turbine engine.

Implementation Method 1

a cooling system using impingement cooling holes to manage thermal loads

Methodology Applied
Scientific EffectImpingement cooling: Convection

Implementation Method 2

actively cooling the components to prevent thermal overload

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3219938B1Blade outer air seal support and method for protecting blade outer air seal
Publication Date: 2021.05.12 RTX CORP
  • EP3219938B1 patent drawingFigure 1
  • EP3219938B1 patent drawingFigure 2~4
  • EP3219938B1 patent drawingFigure 5

AI summary

A blade outer air seal support (100; 400; 500; 700) includes, at least one arc body having a first portion (110; 410; 510) and a second portion (120; 420; 520), a blade outer air seal mounting region (108) defined at least partially between the first portion (110; 410; 510) and the second portion (120; 420; 520), and an interface feature (130; 430; 530) interfacing the first portion (110; 410; 510) and the second portion (120; 420; 520). The interface feature (130; 430; 530) is configured such that axially aligned forces (104) are communicated between the first and second portions (110, 120; 410, 420; 510, 520) through the interface feature (130; 430; 530), bypassing the blade outer air seal mounting region (108). A corresponding blade outer air seal assembly and method for protecting a blade outer air seal are also provided.