Swirled Mini-Mixer Clusters for Fuel-Staged, Axially Staged Combustion
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Solution Overview
Problem
Existing gas turbine engines face challenges in maintaining optimal air-fuel ratios, leading to excessive NOx and particle emissions due to constant bulk inlet air area and varying fuel volume, which conventional injectors fail to address effectively.
Innovation Solution
The implementation of a main injector with multiple sub-element mixers, each comprising a main air nozzle circumscribing a main fuel nozzle, allows for varied air-fuel ratios through distinct operational configurations, including axially staged combustion, to optimize fuel delivery and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional injectors with constant bulk inlet air area are used, then the structure is simple, but the air-fuel ratio cannot be optimized under varying fuel volume conditions, leading to excess NOx and particle emissions
Solution Approach 1:
The injector is divided into multiple sub-element mixers (first, second, third sub-element mixers) with distinct fuel nozzles and air nozzles. Each sub-element mixer can independently control fuel and air flow, enabling separate control of air-fuel ratios for different combustion zones. This segmentation allows optimization of air-fuel mixing for reduced emissions while maintaining manageable structural complexity through modular design
Solution Approach 2:
Different sub-element mixers are configured with different air-fuel ratio characteristics to address local combustion requirements. The first sub-element mixer serves a first combustion zone with one air-fuel ratio, while the second and third sub-element mixers serve a second combustion zone with different air-fuel ratios. This local quality differentiation enables precise control of combustion characteristics in different regions, reducing overall emissions
2Productivity
If multiple sub-element mixers with different air-fuel ratios are implemented, then combustion efficiency and emission control improve, but the injector structure becomes more complex
Solution Approach 1:
The injector is divided into multiple sub-element mixers (first, second, third sub-element mixers) with distinct fuel nozzles and air nozzles. Each sub-element mixer can independently control fuel and air flow, enabling separate control of air-fuel ratios for different combustion zones. This segmentation allows optimization of air-fuel mixing for reduced emissions while maintaining manageable structural complexity through modular design
Solution Approach 2:
Multiple sub-element mixers are integrated into a single injector assembly that serves dual combustion zones. The injector structure performs multiple functions: delivering fuel to different zones, providing air mixing for each zone, and enabling independent air-fuel ratio control for each sub-element. This multi-functionality achieves high combustion efficiency while consolidating complexity into an integrated design
3Adaptability or versatility
If bulk inlet air area is kept constant, then the combustor structure is simple, but optimal air-fuel ratio control under varying fuel volume is not achieved
Solution Approach 1:
The air delivery system is segmented into multiple air nozzles associated with different sub-element mixers. Each air nozzle can independently modulate air flow to its corresponding fuel nozzle, enabling adaptive air-fuel ratio control for each combustion zone. This segmentation provides the adaptability needed for varying fuel volumes while keeping the overall combustor structure relatively simple through distributed control
Solution Approach 2:
The air nozzles in each sub-element mixer are configured to dynamically adjust air flow in response to varying fuel volume conditions. The first air nozzle, second air nozzle, and third air nozzle can independently modulate their respective air flows to maintain optimal air-fuel ratios across different operating conditions. This dynamic response enables adaptability without requiring complex centralized control mechanisms
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 reduces NOx and particle emissions by enabling precise control of air-fuel mixtures, enhancing combustion efficiency and minimizing pollutant discharge.
Implementation Method 1
each comprising a main air nozzle circumscribing a main fuel nozzle... allows for varied air-fuel ratios through distinct operational configurations
Implementation Method 2
Gas turbine engines produce thrust and/or work by combustion
Data Source
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AI summary
A main injector (32) can include multiple sub-element mixers (64A-64N). A first sub-element mixer (64A) includes a first main air nozzle (68A) circumscribing a first main fuel nozzle (68A). A second sub-element mixer (64B) includes a second main air nozzle (68B) circumscribing a second main fuel nozzle (68B). An annular combustor can include a circumferential array of main injectors (32) disposed proximate a pilot injector. Each main injector (32) of the array of main injectors (32) can be oriented with first sub-element mixers (64A) proximate to the pilot injector (30) and second sub-element mixers (64B) spaced axially downstream relative to first sub-element mixers (64A) in a staged configuration.