Gas Turbine Combustor Fuel Injector for Low Emissions

Solution Overview

Problem

Gas turbine engines face challenges in reducing nitrogen oxide (NOx) and soot emissions, particularly due to the high NOx emissions associated with non-premixed pilot flames used in combustor sections.

Innovation Solution

A combustor assembly with a fuel injector assembly featuring a swirler body and nozzle that converges to a throat, incorporating both primary and secondary fuel injectors to manage fuel flow and airflow for both low and high power operating conditions, allowing for the creation of both non-premixed and premixed flames to optimize combustion efficiency and emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a non-premixed pilot flame is used to provide stable combustion, then flame stability is improved, but nitrogen oxide emissions increase

Engineering Contradiction:

Improveflame stabilityVSAvoidnitrogen oxide emissions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The fuel injector assembly is segmented into multiple injectors with different functions: a primary fuel injector for non-premixed combustion and secondary plain jet fuel injectors for premixed combustion. This segmentation allows the system to switch between combustion modes or operate in combination to reduce NOx emissions while maintaining flame stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The combustor system dynamically adjusts the fuel distribution between the primary and secondary injectors based on operating conditions. The control system meters fuel flow to each injector differently in first and second modes, enabling transition from non-premixed to premixed combustion to reduce emissions while maintaining stability.

Inventive Principle:

Principle #15Dynamics

2Reliability

If a non-premixed combustion mode is used, then flame stability is improved, but soot emissions increase

Engineering Contradiction:

Improveflame stabilityVSAvoidsoot emissions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The fuel injector assembly is segmented into multiple injectors with different functions: a primary fuel injector for non-premixed combustion and secondary plain jet fuel injectors for premixed combustion. This segmentation allows the system to switch between combustion modes or operate in combination to reduce soot emissions while maintaining flame stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The combustor system dynamically adjusts the fuel distribution between the primary and secondary injectors based on operating conditions. The control system meters fuel flow to each injector differently in first and second modes, enabling transition from non-premixed to premixed combustion to reduce soot emissions while maintaining stability.

Inventive Principle:

Principle #15Dynamics

3Object-generated harmful factors

If separate control of primary and secondary fuel injectors is implemented, then emissions are reduced, but device complexity increases

Engineering Contradiction:

ImproveemissionsVSAvoidfuel control system complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The fuel injector assembly is designed as a multi-functional unit where the primary and secondary injectors work together to achieve multiple objectives: stable combustion, emission reduction, and adaptability to different operating modes. This integrated design reduces overall system complexity compared to separate control systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effectively reduces NOx and soot emissions by optimizing fuel and air mixing, achieving lower emissions across varying power conditions while maintaining stable flame performance.

Implementation Method 1

accelerating airflow in an injector passage from a first passage section toward a throat defined by a second passage section

Methodology Applied

Scientific EffectFlow acceleration through convergent passage: Venturi Effect

Implementation Method 2

injecting fuel into the first passage section and fuel into the second passage section to establish a single non-premixed flame during a first, different mode, and injecting fuel into the first passage section to establish a non-premixed flame and fuel into the second passage section to establish a premixed flame

Methodology Applied

Scientific EffectFuel and air mixing: Diffusion

Implementation Method 3

injecting fuel into the first passage section and fuel into the second passage section to establish a single non-premixed flame

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS11719158B2Low emissions combustor assembly for gas turbine engine

Publication Date: 2023.08.08 RTX CORP

AI summary

A combustor assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a combustion chamber, and a fuel injector assembly in communication with the combustion chamber that has a swirler body situated about a nozzle to define an injector passage that converges to a throat. The throat is defined at a distance from the combustion chamber. The nozzle includes a primary fuel injector and an array of secondary plain jet fuel injectors.