Heat Shield Panel Cooling and Dilution in Gas Turbine Combustors

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Solution Overview

Problem

Heat shield panels in multi-layer combustor liners of gas turbine engines face intense heat, leading to deterioration and the need for frequent replacement, despite existing film cooling methods which are insufficient for effective heat management.

Innovation Solution

Incorporating larger cooling openings and a fence structure in the heat shield panels to allow greater airflow for both cooling and dilution of combustion gases, utilizing a portion of the dilution air to enhance cooling efficiency and extend the lifespan of the panels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If film cooling holes are used in heat shield panels, then cooling is provided to the panel surface, but the cooling efficiency is insufficient to prevent deterioration

Engineering Contradiction:

Improveheat shield panel temperatureVSAvoidheat shield panel durability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The cooling system is segmented into multiple functional zones: film cooling holes for surface cooling, cooling passages for internal heat dissipation, and dilution openings for combustion gas management. This segmentation allows each component to optimize its specific cooling function, collectively achieving sufficient temperature control to prevent panel deterioration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Cooling air acts as an intermediary substance that transfers heat from the heat shield panel to the combustion chamber environment. The air flows through multiple pathways (film cooling, internal passages, dilution openings) to efficiently carry away heat, preventing panel temperature from reaching deterioration thresholds

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If cooling airflow holes are increased in the outer shell, then cooling efficiency improves, but dilution of combustion gases is reduced

Engineering Contradiction:

Improvecombustor liner cooling efficiencyVSAvoidcombustion gas dilution

Core Design Contradiction:

TemperatureVSQuantity of substance

Solution Approach 1:

The airflow system is segmented into distinct functional openings: cooling airflow holes in the outer shell for heat dissipation, and separate dilution openings for combustion gas mixing. This segmentation allows independent optimization of cooling efficiency and gas dilution without compromising either function

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Cooling air serves multiple functions simultaneously: it cools the outer shell through convection, provides film cooling to heat shield panels, and contributes to dilution of combustion gases when discharged through dilution openings. This multi-functionality resolves the contradiction by making the same fluid resource serve both cooling and dilution purposes

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Temperature

If conventional film cooling is used in heat shield panels, then some cooling is provided, but panel deterioration continues and frequent replacement is needed

Engineering Contradiction:

Improveheat shield panel surface temperatureVSAvoidheat shield panel service life

Core Design Contradiction:

TemperatureVSDuration of action of stationary object

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system provides excessive cooling action by combining multiple cooling mechanisms (film cooling, internal passages, dilution openings) that collectively deliver more cooling capacity than the minimum required. This ensures panel temperatures remain well below deterioration thresholds throughout the extended service life

Inventive Principle:

Principle #16Partial or excessive action

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

This approach increases the combustor airflow utilization for cooling to up to 70% while maintaining dilution of combustion gases, reducing the frequency of heat shield panel replacements and improving overall engine performance.

Implementation Method 1

Cooling airflow holes may be included in the outer shell to allow a flow of cooling air to pass therethrough

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

the heat shield panels may include cooling holes to provide a film cooling to the surface of the heat shield panels

Methodology Applied

Scientific EffectFilm cooling:

Implementation Method 3

utilizing a portion of the dilution air to enhance cooling efficiency and extend the lifespan of the panels

Methodology Applied

Scientific EffectDilution:

Data Source

PatentUS12055293B2Combustor having dilution cooled liner

Publication Date: 2024.08.06 GENERAL ELECTRIC CO

AI summary

A combustor for a gas turbine has a combustor liner including an upstream liner portion, and a downstream liner portion. The upstream liner portion includes an outer shell and a heat shield panel, with a baffle cavity therebetween. The outer shell includes an outer shell cooling opening for providing a flow of compressed air to the baffle cavity, and the heat shield panel includes a heat shield panel cooling opening at a downstream end of the heat shield panel. A fence is arranged at a downstream side of the heat shield panel cooling opening and extends beyond a hot side surface of the heat shield panel into a combustion chamber. The heat shield panel cooling opening provides a flow of the compressed air therethrough from the baffle cavity for cooling of the heat shield panel and for providing at least partial dilution of combustion gases within the combustion chamber.