Combustor Dilution Hole Cooling Circuit

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Solution Overview

Problem

Gas turbine combustors experience liner distress due to air jets in cross-flow, which disrupt cooling, increase heat transfer, and create biased distress patterns, primarily due to the interaction of air jets with the fuel-air mixture and the combustor liner materials, leading to oxidation and melting.

Innovation Solution

A cooling circuit is formed on the combustor panel or liner wall using a metal coating or plating over cooling channels, with an insert material that is subsequently removed, and post-processing techniques such as thermal barrier coating or electrodischarge machining to enhance cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If air jets are introduced through dilution and trim holes to control combustion, then combustion spatial and temporal characteristics are improved, but liner distress (oxidation and melting) occurs due to disrupted cooling and increased heat transfer

Engineering Contradiction:
Improvecombustion controlVSAvoidliner distress
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by introducing cooling air through holes in the liner wall before the hot combustion gases reach critical temperatures. The cooling air is pre-positioned to counteract the heat transfer and prevent liner distress before oxidation and melting occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses cooling air as an intermediary substance introduced through dilution and trim holes. This cooling air acts as a mediator between the hot combustion gases and the liner wall, reducing heat transfer and preventing direct thermal damage to the liner material.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If air jets are used to tailor combustion, then emissions and performance are improved, but secondary flows and vortical structures disrupt cooling and drive hot gases to liner surfaces

Engineering Contradiction:
Improveemissions and performanceVSAvoidliner surface temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies local quality by introducing cooling air at specific locations through holes in the liner wall where hot gases are driven by secondary flows. The cooling is localized to the areas most affected by vortical structures and secondary flows, targeting specific hot spots on the liner surface.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cooling air is introduced in advance to counteract the temperature increase caused by secondary flows and vortical structures before hot gases can drive the liner surface temperature to dangerous levels.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If dilution holes are present to provide feed air, then combustion support is improved, but flow acceleration around holes increases heat transfer and strengthens secondary flows

Engineering Contradiction:
Improvefeed airVSAvoidheat transfer
Core Design Contradiction:
Quantity of substanceVSStress or pressure

Solution Approach 1:

The patent introduces cooling air through the same dilution and trim holes used for combustion support. This cooling air acts as an intermediary that reduces heat transfer to the liner wall, counteracting the increased heat transfer caused by flow acceleration around the holes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameters of the air flow through dilution holes by introducing cooling air that modifies the temperature and velocity profiles. This parameter change reduces the heat transfer to the liner wall while maintaining the necessary feed air quantity for combustion.

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 effectively reduces liner distress by improving cooling efficiency and preventing oxidation, thereby extending the lifespan of combustor components and maintaining performance.

Implementation Method 1

A cooling circuit is formed on the combustor panel or liner wall

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

cooling channels with an insert material that is subsequently removed

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

post-processing techniques such as thermal barrier coating

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3018415B1Combustor dilution hole cooling
Publication Date: 2020.01.01 UNITED TECH CORP
  • EP3018415B1 patent drawingFigure 1A
  • EP3018415B1 patent drawingFigure 1B
  • EP3018415B1 patent drawingFigure 2

AI summary

Method 300A for forming a cooling circuit in at least one of a combustor panel or liner wall of an aircraft engine. The method includes producing 302A a substrate with the cooling circuit formed in the substrate, where the cooling circuit is located in proximity to an aperture associated with the at least one of a panel or liner wall.