Radial Fuel Biasing in Axial Staged Combustor
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Solution Overview
Problem
Gas turbine engines face challenges in minimizing nitrogen oxide (NOx) emissions and combustion instabilities, particularly in radial-staged lean combustors, due to concentrated heat release and weak flame holding at certain operating conditions.
Innovation Solution
A radial fuel injection system with a swirler and fuel nozzle that provides a biased radial fuel distribution, enriching specific areas within the combustor to stabilize combustion and reduce NOx emissions, utilizing a fuel divider valve to selectively control fuel flow between sets of fuel injector orifices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If lean-staged liquid-fueled combustion is used to reduce NOx emissions, then nitrogen oxide emissions are minimized, but combustion instabilities occur due to heat release concentration and weak flame holding
Solution Approach 1:
The patent applies local quality by creating a non-uniform fuel distribution within the swirler, specifically enriching the outer radial regions while maintaining lean combustion in the core. This is achieved through strategically positioned fuel injector orifices that deliver fuel preferentially to specific radial zones, allowing different regions of the combustor to have different fuel-air ratios optimized for their specific functions: stable flame holding in enriched zones and low emissions in lean zones
Solution Approach 2:
The fuel injection system is segmented into multiple sets of fuel injector orifices positioned at different radial locations within the swirler. The patent divides the fuel delivery function across multiple zones, with each set of orifices serving a specific radial region. This segmentation allows independent optimization of fuel distribution patterns to simultaneously achieve stable combustion in certain zones and low emissions in others
2Object-generated harmful factors
If main stage air is introduced to dilute the pilot stage fuel-air ratio for emissions control, then NOx emissions are reduced, but flame holding becomes weak at certain operating conditions
Solution Approach 1:
The patent creates localized fuel-enriched regions within the swirler to provide reliable flame holding in specific zones while maintaining overall lean combustion for emissions control. The fuel injector orifices are positioned to create pockets of richer mixture that serve as stable flame anchors, while the broader combustor environment remains lean to minimize NOx formation
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 enhances combustion stability, reduces NOx emissions, and improves flameholding by providing a fuel-enriched bias to critical areas within the combustor, mitigating combustion instabilities and meeting stringent emission controls.
Implementation Method 1
the fuel nozzle operable to provide a biased radial fuel distribution within the swirler
Implementation Method 2
Combustion of hydrocarbon fuel in the presence of pressurized air may produce nitrogen oxide (NOX) emissions
Implementation Method 3
A radial fuel injection system with a swirler and fuel nozzle that provides a biased radial fuel distribution
Implementation Method 4
utilizing a fuel divider valve to selectively control fuel flow between sets of fuel injector orifices
Data Source
AI summary
An injector of a radial fuel injection system for a combustor of a gas turbine engine includes a swirler; and a fuel nozzle located within the swirler, the fuel nozzle located within the swirler, the fuel nozzle operable to provide a biased radial fuel distribution within the swirler. A method of controlling a fuel flow to a combustor of a gas turbine engine includes selectively controlling a biased radial fuel distribution within a swirler of a radial fuel injection system.