Spiraling Lean Injectors Reduce Thermal Gradients

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing combustor designs face issues with flame holding and vortex shedding due to the perpendicular alignment of late lean injectors, leading to high thermal gradients and reduced hardware life, as well as increased NOx production at higher combustion gas temperatures.

Innovation Solution

The system includes late lean injectors with a spiraling, ovular cross-section, and tapered ends that are angled with respect to the combustion chamber, reducing flame holding and vortex shedding by enhancing mixing and penetration of the lean fuel-air mixture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If late lean injectors are aligned perpendicular to the flow of combustion gases, then the lean fuel-air mixture can be injected into the combustion chamber, but large vortices are produced that recirculate hot combustion gases back to the surface of the combustion chamber, producing high thermal gradients and shortening hardware life

Engineering Contradiction:

Improvecombustion gas temperatureVSAvoidhardware life

Core Design Contradiction:

TemperatureVSDuration of action of stationary object

Solution Approach 1:

The tube is angled relative to the flow of combustion gases rather than being perpendicular, creating an asymmetric injection pattern that reduces vortex formation and hot gas recirculation, thereby reducing thermal gradients and extending hardware life

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The tube has a curved or spiraling configuration instead of a straight perpendicular alignment, which modifies the flow pattern to reduce large vortex formation and associated thermal gradients that shorten hardware life

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Ease of manufacture

If tubes have a substantially constant cross section, then the structure is simple to manufacture, but conditions around the late lean injectors become susceptible to localized flame holding

Engineering Contradiction:

Improvetube manufacturing simplicityVSAvoidflame holding susceptibility

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The tube cross-section varies along its length rather than remaining constant, with specific sections having different dimensions to prevent flame holding while maintaining manufacturability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The tube cross-sectional parameters are changed along the length of the tube to create flow conditions that prevent localized flame holding, while the overall design remains manufacturable

Inventive Principle:

Principle #35Parameter changes

3Power

If higher combustion gas temperatures are used, then the thermodynamic efficiency of the combustor is improved, but the production of nitrogen oxides (NOx) increases

Engineering Contradiction:

Improvethermodynamic efficiencyVSAvoidnitrogen oxides production

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

A portion of the compressed working fluid is pre-cooled in the flow sleeve before mixing with fuel in the tube, creating a cooler lean fuel-air mixture that when injected raises combustion temperature efficiently while the cooling effect helps control NOx formation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The flow sleeve acts as an intermediary cooling element between the compressed working fluid and the fuel mixture, pre-cooling the working fluid to enable more efficient combustion with reduced NOx production

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

This design increases combustion gas temperatures without increasing NOx production, reduces flame holding and vortex recirculation, and enhances thermodynamic efficiency while prolonging hardware life by minimizing thermal gradients.

Implementation Method 1

A tube provides fluid communication for the working fluid to flow through the flow sleeve and the liner and into the combustion chamber

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

The compressed working fluid exits the compressor and flows into a combustion chamber

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

a portion of the compressed working fluid exiting the compressor may flow through the tubes to mix with fuel to produce a lean fuel-air mixture

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 4

The lean fuel-air mixture may then be injected by the tubes into the combustion chamber, resulting in additional combustion that raises the combustion gas temperature

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 5

the compressed working fluid mixes with fuel and ignites to generate combustion gases having a high temperature and pressure

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentEP2639507B1System for supplying a working fluid to a combustor

Publication Date: 2019.09.04 GENERAL ELECTRIC CO

Figure 1
Figure 2
Figure 3~4

AI summary

A system for supplying a working fluid 22 to a combustor 14 includes a combustion chamber 38, a liner 46 that circumferentially surrounds at least a portion of the combustion chamber 38, and a flow sleeve 48 that circumferentially surrounds at least a portion of the liner 46. A tube 60 provides fluid communication for the working fluid 22 to flow through the flow sleeve 48 and the liner 46 and into the combustion chamber 38, and the tube 60 spirals between the flow sleeve 48 and the liner 46.