Tangential On-Board Injector With Integral Abradable Seal

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Solution Overview

Problem

The existing abradable seals in gas turbine engines, typically brazed onto components, are fragile and costly to manufacture, with brazing processes risking damage during installation and resulting in inconsistent joint shapes due to uneven brazing flux distribution.

Innovation Solution

The use of additive manufacturing to create a monolithic, integral abradable seal with uniform joints and a honeycomb structure, eliminating the need for brazing and enhancing the seal's durability and consistency, while allowing for deeper penetration of knife edge seals without damaging the abradable component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If brazing is used to attach abradable seals to components, then the seal can be installed, but the seal may be damaged during installation and manufacturing time increases

Engineering Contradiction:
Improveseal durabilityVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The abradable seal is merged with the TOBI as a single integral component manufactured via additive manufacturing, eliminating the separate brazing attachment step. This combines what were previously two separate manufacturing operations into one unified process, resolving the contradiction by removing the time-consuming brazing step while maintaining seal integrity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mechanical brazing process is replaced with an additive manufacturing process that directly forms the integral seal structure. This substitution eliminates the thermal and mechanical stresses of brazing that could damage the seal, while also reducing manufacturing time by eliminating the brazing cycle.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If brazing is used to attach abradable seals, then the seal can be installed, but inconsistent joint shapes result due to uneven brazing flux distribution

Engineering Contradiction:
Improveseal performance consistencyVSAvoidjoint shape consistency
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

By merging the seal and TOBI into one integral component, the invention eliminates the joint region entirely. This removes the source of manufacturing precision problems associated with brazing flux distribution, as there is no separate joint to be formed. The additive manufacturing process ensures uniform material properties throughout the entire structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The brazing process is replaced with additive manufacturing, which deposits material in a controlled, layer-by-layer manner. This substitution eliminates the unpredictable flux distribution and joint formation issues of brazing, ensuring consistent and precise geometry throughout the integral seal structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If knife edge seals penetrate deeply to improve sealing, then sealing effectiveness increases, but the fragile abradable seal may be damaged

Engineering Contradiction:
Improvesealing effectivenessVSAvoidseal fragility
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The integral design of the abradable seal with the TOBI creates a more robust structure that can withstand deeper knife edge penetration. The additive manufacturing process creates a unified structure where the seal is not a separate fragile component but an integrated part of the TOBI, able to handle the mechanical stresses of deep sealing contact.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The abradable seal is manufactured using Inconel 718, a high-strength nickel-based superalloy that provides both the required softness for abradable sealing and the structural integrity to withstand deep knife penetration. This material selection resolves the contradiction by providing a material that is both compliant enough to seal effectively and strong enough to resist damage.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3147049B1Method of making a tangential on-board injector
Publication Date: 2021.11.17 RTX CORP
  • EP3147049B1 patent drawingFigure 1
  • EP3147049B1 patent drawingFigure 2
  • EP3147049B1 patent drawingFigure 3A~3B

AI summary

A method of making a component (52, 52') includes creating a computer file defining the component (52, 52') in layers, the component (52, 52') including: a body (58) including a sealing portion (64, 64'); and an abradable seal (66, 66') extending from the sealing portion (64, 64'); and building the component (52, 52') using an additive manufacturing process that builds the component (52, 52') on a layer-by-layer basis such that the abradable seal (66, 66') is integral to the body (58).