Rich-Lean Fuel Nozzle Assembly for Hydrogen Combustion Stability
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Solution Overview
Problem
Turbine engines using hydrocarbon fuels produce environmentally unwanted byproducts such as NOx, CO, UHC, and sulfur oxides, while hydrogen fuel, though cleaner, poses challenges like flashback and flameholding due to rapid dispersion and mixing issues.
Innovation Solution
The use of fuel nozzle assemblies with outer and inner fluid passages providing swirling flows and counter-swirl configurations, along with rich and lean fuel-air mixtures, to enhance mixing and stability, reducing NOx emissions and flameholding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrogen fuel is used to reduce environmentally unwanted byproducts, then emissions are reduced, but flashback and flameholding risks increase due to rapid dispersion and mixing
Solution Approach 1:
The fuel nozzle assembly is divided into multiple fluid passages (first and second fluid passages) that separately deliver different fuel-air mixture ratios to the combustion chamber. This segmentation allows precise control over fuel distribution, preventing rapid dispersion that causes flashback while maintaining clean combustion
Solution Approach 2:
The system varies the equivalence ratio parameter by providing both rich and lean fuel-air mixtures through different fluid passages. This parameter control enables optimization of combustion stability to prevent flameholding while maintaining low emissions, directly addressing the contradiction between clean burning and safety
2Speed
If gaseous fuel is used, then mixing speed increases, but flame spread control becomes more difficult increasing flashback risk
Solution Approach 1:
Different regions of the combustion chamber receive different fuel-air mixture qualities through the first and second fluid passages. The rich mixture from one passage and lean mixture from another create localized combustion zones that control flame spread direction and intensity, managing the rapid mixing characteristics of gaseous fuel
Solution Approach 2:
The controller receives feedback about combustion conditions and adjusts the fuel-air mixture ratios delivered through different fluid passages in real-time. This feedback control manages flame spread dynamics by modulating the rich and lean mixture proportions, maintaining stability despite rapid gaseous fuel mixing
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 provides greater flame stability, lower NOx emissions, and reduced flashback, while maintaining efficient combustion dynamics using gaseous hydrogen fuel without diluents.
Implementation Method 1
outer and inner fluid passages providing swirling flows and counter-swirl configurations, along with rich and lean fuel-air mixtures, to enhance mixing and stability
Implementation Method 2
air and fuel are mixed, and then the fuel is burned in the presence of the air to produce hot gas
Data Source
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AI summary
A gas turbine engine (10), comprising a compressor section (12), combustion section (14), and turbine section (16) in serial flow arrangement, with the combustion section (14) comprising: a combustor liner (40) that at least partially defines a combustion chamber (50); and a gaseous fuel nozzle assembly (48, 348), comprising: a rich fuel supply (102) configured to provide a rich mixture of gaseous fuel and air; a lean fuel supply (104) configured to provide a lean mixture of gaseous fuel and air, the lean mixture having a lower equivalence ratio than the rich mixture; a wall (46) coupled with the combustor liner (40); a rich fluid passage (110, 410) fluidly coupled to the rich fuel to emit the rich mixture into the combustion chamber (50); and a lean fluid passage (112, 412) fluidly coupled to the lean fuel supply (104) to emit the lean mixture into the combustion chamber (50).