Gas Turbine Igniter Assembly Radial Stability

Solution Overview

Problem

The existing ignition systems in gas turbine engines face issues with thermal fatigue and inconsistent ignition due to varying thermal growth rates and g-forces, causing the ignition tip to either immerse excessively in hot combustion gases or lift out of the combustion chamber, affecting light-off and overall engine performance.

Innovation Solution

An igniter assembly with a radially extending igniter tube, a nut, a biasing member, a flexible seal, and a retention collar that couples to a mounting ring on the outer liner, providing radial and axial stability to maintain the ignition tip's position within the combustion chamber, reducing thermal fatigue and ensuring consistent ignition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ignition tip is positioned radially through the outer casing and outer liner, then the ignition system can provide a spark to ignite the fuel/air mixture, but varying thermal growth rates and g-forces cause the ignition tip to over immerse into hot combustion gases or lift radially out of the opening, resulting in thermal fatigue or affected light-off capability

Engineering Contradiction:

Improveignition reliabilityVSAvoidthermal fatigue

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The igniter tube is made movable relative to the outer liner, allowing it to dynamically adjust its position in response to thermal growth and g-force variations. The movable connection enables the igniter tube to maintain optimal positioning without causing thermal fatigue or losing light-off capability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system allows for changes in the relative position parameters between the igniter tube and outer liner. By permitting controlled movement in radial and axial directions, the system adapts to varying thermal and mechanical conditions while maintaining ignition reliability

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the ignition tip is fixed relative to the outer casing, then the structure is simple, but varying thermal growth rates cause the ignition tip to over immerse into hot combustion gases, resulting in thermal fatigue

Engineering Contradiction:

Improveigniter assembly complexityVSAvoidignition reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The igniter tube is made movable relative to the outer liner, allowing it to dynamically adjust its position in response to thermal growth and g-force variations. The movable connection enables the igniter tube to maintain optimal positioning without causing thermal fatigue or losing light-off capability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system allows for changes in the relative position parameters between the igniter tube and outer liner. By permitting controlled movement in radial and axial directions, the system adapts to varying thermal and mechanical conditions while maintaining ignition reliability

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If the ignition tip is fixed relative to the outer liner, then the positioning is stable, but the system cannot accommodate varying thermal growth rates and g-forces, potentially causing the ignition tip to lift out of the opening

Engineering Contradiction:

Improveignition tip positioning stabilityVSAvoidadaptability to thermal and mechanical variations

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The igniter tube is made movable relative to the outer liner, allowing it to dynamically adjust its position in response to thermal growth and g-force variations. The movable connection enables the igniter tube to maintain optimal positioning without causing thermal fatigue or losing light-off capability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system allows for changes in the relative position parameters between the igniter tube and outer liner. By permitting controlled movement in radial and axial directions, the system adapts to varying thermal and mechanical conditions while maintaining ignition reliability

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

The solution ensures the ignition tip remains fixed relative to the outer liner, improving ignition reliability, reducing thermal and mechanical stress, and enhancing durability and safety while minimizing maintenance costs.

Implementation Method 1

A biasing member at least partially surrounds a portion of the igniter tube within the outer housing. The biasing member extends between an inner surface of a top portion of the outer housing and the nut.

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS10041413B2Igniter assembly for a gas turbine engine

Publication Date: 2018.08.07 GENERAL ELECTRIC CO

AI summary

In one aspect the present subject matter is directed to an igniter assembly for a gas turbine engine. The igniter assembly includes an outer housing and an igniter tube that extends radially through the outer housing. The igniter tube includes an ignition tip, a nut coupled to the igniter tube and disposed at least partially within the outer housing and a biasing member that extends between an inner surface of a top portion of the outer housing and the nut. A flexible seal extends radially inwardly from a bottom side of the nut and a retention collar is coupled to the igniter tube proximate to the ignition tip. The retention collar is configured to couple to a mounting ring connected to an outer liner of a combustor for the gas turbine engine.