Concentric Fuel Nozzle Array for Uniform Lean Combustion
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Solution Overview
Problem
Existing multi-point lean direct injection (MLDI) systems in gas turbine engines face challenges in achieving uniform fuel and air distribution, leading to temperature variations and increased pollutant emissions like NOx.
Innovation Solution
A fuel injection system with multiple concentric rings of fuel nozzles, each with varying airflow and fuel flow areas, channel heights, and discrete or vane passage configurations to ensure uniform air and fuel distribution, compensating for different nozzle volumes and pressures to achieve consistent combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-point or conventional multi-point fuel injection system is used, then the system is simple in structure, but the fuel and air distribution is non-uniform leading to temperature variations and increased pollutant emissions
Solution Approach 1:
The fuel injection system is segmented into multiple concentric rings of nozzles, with each ring containing multiple nozzles distributed circumferentially. This segmentation allows different radial zones to receive appropriately scaled fuel and air flows, achieving uniform distribution across the combustor while maintaining a modular, manageable structure.
Solution Approach 2:
Different radial zones of the combustor are provided with different nozzle configurations. Outer nozzles have larger airflow and fuel flow areas compared to inner nozzles, matching the local volumetric requirements of each zone. This local differentiation ensures uniform combustion across the entire combustor volume without requiring excessive overall complexity.
2Manufacturing precision
If all nozzles have equal airflow areas, then the nozzle design is simple, but the different nozzle volumes result in non-uniform fuel distribution and temperature variations
Solution Approach 1:
Each nozzle's airflow area and fuel flow area are locally optimized based on its radial position. Outer nozzles serving larger combustor volumes are designed with larger airflow areas than inner nozzles. This local quality adjustment ensures that each nozzle delivers proportionate fuel and air flows to its designated zone, achieving uniform combustion without requiring all nozzles to have identical complex geometries.
Solution Approach 2:
The airflow area and fuel flow area parameters are systematically varied across the nozzle array based on radial position. This parameter change strategy allows the system to accommodate different nozzle volumes and pressures while maintaining uniform combustion characteristics throughout the combustor.
3Manufacturing precision
If outer nozzles serve larger combustor volumes, then the fuel distribution can be optimized, but the airflow areas must be larger increasing the device complexity
Solution Approach 1:
The airflow area of each nozzle is locally adapted to the combustor volume it serves. Outer nozzles, which service larger radial zones, are designed with larger airflow areas than inner nozzles. This local quality differentiation achieves uniform fuel distribution across varying volumes while keeping the overall design systematic and manageable through consistent scaling principles.
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 system ensures uniform combustion, reducing temperature variations and pollutant emissions by providing proportional air and fuel distribution across the combustor, enhancing combustion efficiency and reducing NOx production.
Implementation Method 1
The second fuel flow area can be smaller than the first fuel flow area in proportion to how much smaller the second airflow area is relative to the first air flow area. The third fuel flow area can be smaller than the second fuel flow area in proportion to how much smaller the third airflow area is relative to the second air flow area.
Data Source
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AI summary
A fuel injection system (100) for a gas turbine engine (102) includes a first plurality of fuel nozzles (110) arrayed in a circular pattern. Each of the nozzles in the first plurality of fuel nozzles (110) includes a first airflow area defined therethrough. A second plurality of fuel nozzles (112) radially inward from the first plurality of fuel nozzles (110). Each of the nozzles in the second plurality of fuel nozzles (112) includes a second airflow area defined therethrough. The first airflow area is larger than the second airflow area. A third plurality of fuel nozzles (114) can be radially inward from the second plurality of fuel nozzles (112). Each of the nozzles in the third plurality of fuel nozzles (114) can include a third airflow area defined therethrough. The second airflow area can be larger than the third airflow area.