Flexible Dome-Deflector Joints for Gas Turbine Combustor Thermal Stress

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Solution Overview

Problem

Bolted joints in gas turbine combustors experience thermal expansion and vibrations due to intense heat and combustion dynamics, leading to potential stress and breakdown.

Innovation Solution

Implementing flexible compliant joints, such as flexible bolts or couplers with heli-coil or serrated shanks, and ripple-shaped washers, which provide flexibility and cooling to accommodate thermal loads and vibrations, connecting the dome and deflector or liner shell and panels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid bolted joints are used to connect dome and deflector, then structural strength is improved, but thermal expansion and vibrations cause stress and potential breakdown

Engineering Contradiction:

Improvejoint strengthVSAvoidjoint reliability under thermal load

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the physical parameters of the connecting members by introducing flexibility through heli-coil shanks and serrated configurations. These modifications allow the joints to accommodate thermal expansion and vibration while maintaining structural integrity, resolving the contradiction between strength and reliability under thermal load.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent transforms rigid static joints into dynamic flexible joints that can adapt to thermal expansion and vibration. The flexible connecting members with heli-coil and serrated features enable the joint to move and absorb energy, maintaining reliability under varying thermal and mechanical conditions.

Inventive Principle:

Principle #15Dynamics

2Reliability

If flexible connecting members are used to accommodate thermal expansion, then joint reliability is improved, but connection strength may be reduced

Engineering Contradiction:

Improvejoint reliability under thermal loadVSAvoidjoint strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent employs composite structural features combining rigid and flexible elements. The heli-coil shanks and serrated features create a composite connecting member that exhibits both flexibility for thermal accommodation and sufficient strength for structural support, resolving the contradiction between reliability and strength.

Inventive Principle:

Principle #40Composite materials

3Temperature

If cooling airflow is introduced through flexible connecting members, then thermal management is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvejoint temperatureVSAvoidmanufacturing complexity

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent utilizes the flexible connecting members as dual-purpose components that provide both mechanical connection and thermal management. The flexible shanks with integrated cooling passages serve as both structural elements and cooling channels, reducing the need for separate cooling systems and managing the manufacturing complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

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 flexible joints effectively reduce stress on the connections by allowing for thermal expansion and vibration absorption, enhancing the durability and reliability of the combustor components.

Implementation Method 1

The flexible bolt includes a flexible shank portion... providing flexibility and cooling to accommodate thermal loads and vibrations

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The flexible bolt... providing flexibility and cooling to accommodate thermal loads and vibrations

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS11781753B2Combustor dome-deflector and liner having flexible connections

Publication Date: 2023.10.10 GENERAL ELECTRIC CO

AI summary

A combustor for a gas turbine includes a dome, and a deflector connected to the dome to define a baffle cavity therebetween, the deflector having a deflector cold side adjacent to the baffle cavity and a deflector hot side adjacent to a combustion chamber. At least one dome-deflector connecting member connects the dome and the deflector to each other. The dome-deflector connecting member forms a flexible joint between the dome and the deflector.