Converging-Diverging Combustor Liner for NOx Reduction

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Solution Overview

Problem

Conventional gas turbine engines face challenges in quickly and efficiently quenching hot combustion gases from the primary combustion zone, leading to high NOx emissions due to inadequate dilution of combustion gases in the combustion chamber.

Innovation Solution

A combustor liner with a converging-diverging portion in the dilution zone, featuring dilution airflow openings arranged in the throat section, reduces the cross-sectional area, allowing for deeper penetration of dilution airflow and improved quenching of hot combustion gases, thereby reducing NOx emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a conventional straight combustor liner is used, then the structure is simple and easy to manufacture, but the quenching of hot combustion gases is insufficient leading to high NOx emissions

Engineering Contradiction:

ImproveNOx emissionsVSAvoidcombustor liner structure

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The combustor liner incorporates a converging-diverging geometry with curved surfaces instead of a straight configuration. The converging section narrows the flow passage while the diverging section expands it, creating a complex three-dimensional flow path that enhances dilution air mixing and quenching of hot combustion gases, thereby reducing NOx emissions.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the combustor liner by introducing variable cross-sectional area along the flow direction. The converging section reduces the flow area to increase velocity and mixing, while the diverging section expands the area to accommodate the diluted flow, optimizing the quenching process and emissions reduction.

Inventive Principle:

Principle #35Parameter changes

2Object-generated harmful factors

If dilution air flow is increased to quench combustion gases, then NOx emissions are reduced, but the flow distribution and mixing efficiency are insufficient in conventional straight liners

Engineering Contradiction:

ImproveNOx emissionsVSAvoidflow distribution and mixing efficiency

Core Design Contradiction:

Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The curved converging-diverging geometry creates favorable flow patterns that enhance mixing between dilution air and combustion gases. The curvature induces secondary flows and turbulence that improve homogeneity of the diluted mixture, ensuring efficient quenching and uniform temperature distribution.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The converging-diverging section acts as an intermediary zone that facilitates the interaction between dilution air and hot combustion gases. This intermediate region provides the necessary residence time and flow conditions for effective mixing and heat transfer, enabling efficient quenching before the gases enter the turbine.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 implementation of the converging-diverging combustor liner design enhances the quenching of hot combustion gases, resulting in reduced NOx emissions and improved cooling efficiency within the dilution zone.

Implementation Method 1

Methodology Applied

Scientific EffectVenturi effect: Venturi Effect

Implementation Method 2

providing a flow of dilution air from a passage surrounding the combustor liners into a dilution zone of the combustion chamber

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

enhances the quenching of hot combustion gases, resulting in reduced NOx emissions and improved cooling efficiency within the dilution zone

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS11747019B1Aerodynamic combustor liner design for emissions reductions

Publication Date: 2023.09.05 GENERAL ELECTRIC CO

AI summary

A combustor liner has an annular outer liner and an annular inner liner that define a combustion chamber therebetween, the combustion chamber having a dilution zone. The annular outer liner and the annular inner liner each has a converging-diverging section extending into the dilution zone of the combustion chamber that form a throat between them. Each of the converging-diverging sections includes at least one dilution opening defined through the respective converging-diverging section at the throat for providing a flow of an oxidizer through a respective liner to the dilution zone of the combustion chamber.