Gas Turbine Combustor Nozzle Layout for Combustion Dynamics Attenuation
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Solution Overview
Problem
Existing combustion systems in gas turbine engines face challenges in simultaneously reducing emissions, attenuating combustion dynamics, and maintaining a uniform circumferential temperature profile while achieving desired energy output, often leading to inefficiencies and adverse effects on engine hardware.
Innovation Solution
A combustion system with alternating circumferential arrangements of richer and leaner burning fuel nozzles, where fuel is split to maintain a desired overall fuel-air ratio, altering local stoichiometry and flame structure to suppress combustion dynamics and emissions, and mitigate temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If staged combustion with on/off fuel nozzles is used to reduce emissions, then CO and UHC emissions are reduced, but combustion efficiency is lowered resulting in emissions elsewhere and increased combustion dynamics
Solution Approach 1:
The patent applies local quality by providing different fuel supplies to different nozzles within the same combustor. Specifically, a first plurality of nozzles receives a first supply of fuel while a second plurality of nozzles receives a second supply of fuel, allowing each nozzle group to operate at optimal local conditions for emissions reduction while maintaining overall combustion efficiency.
Solution Approach 2:
The combustor is segmented into multiple nozzle groups with different fuel supplies. The fuel system is divided into a first fuel supply line and a second fuel supply line that can independently control fuel flow to different nozzle groups, enabling staged combustion without sacrificing overall efficiency.
2Reliability
If on/off arrangement of fuel nozzles is used for staged combustion, then some lean blow-out benefits are provided at low power, but combustion dynamics are not reduced and circumferential temperature variations increase
Solution Approach 1:
Different nozzle groups are provided with different fuel-air mixture qualities. The first plurality of nozzles receives a first fuel supply while the second plurality receives a second fuel supply, creating localized variations in mixture strength that provide LBO protection while the overall distribution maintains temperature uniformity.
Solution Approach 2:
The fuel supply system is made dynamic by allowing the fuel management system to selectively activate or deactivate different fuel supply lines based on operating conditions. This enables adaptation to different power levels while maintaining optimal temperature distribution and reducing combustion dynamics.
3Object-generated harmful factors
If selective fuel injection to sectors of on/off fuel nozzles is used, then emissions are reduced, but combustion process is attenuated at outer edges of individual combustion zones resulting in lowered combustion efficiency
Solution Approach 1:
The combustor is divided into multiple combustion zones, each served by its own plurality of nozzles with independent fuel supply control. This segmentation allows each zone to operate efficiently while collectively reducing emissions through coordinated fuel management across all zones.
Solution Approach 2:
The fuel management system performs multiple functions simultaneously: it controls emissions reduction, maintains combustion efficiency, and regulates temperature distribution. The coordinated control of multiple fuel supply lines to multiple nozzle groups achieves these competing objectives through a unified management approach.
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 effectively suppresses combustion dynamics, reduces emissions, and improves lean blow-out margin by maintaining a uniform fuel-air ratio and mitigating temperature non-uniformities, enhancing engine stability and operability.
Implementation Method 1
igniting the rich fuel-air mixture and the lean fuel-air mixture to produce an overall fuel-air ratio at a combustion chamber of the combustion system
Data Source
AI summary
The present disclosure is directed to a method of operating a combustion system to attenuate combustion dynamics. The method includes flowing, via a compressor section, an overall supply of air to the combustion system; flowing, via a fuel supply system, an overall flow of fuel to the combustion system; flowing, to a first fuel nozzle of the combustion system, a first supply of fuel defining a richer burning fuel-air mixture at the first fuel nozzle; flowing, to a second fuel nozzle of the combustion system, a second supply of fuel defining a leaner burning fuel-air mixture at the second fuel nozzle; and igniting the richer burning fuel-air mixture and the leaner burning fuel-air mixture to produce an overall fuel-air ratio at a combustion chamber of the combustion system.