Fuel Injector With Segmented Pegs For NOx Reduction
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Solution Overview
Problem
Gas turbines produce air-polluting emissions like NOx and carbon monoxide due to the oxidation of molecular nitrogen in the combustor, which is influenced by temperature and residence time, and existing fuel injection methods either increase fuel consumption or fail to effectively manage these factors.
Innovation Solution
A fuel injector design featuring a plurality of fuel vanes and pegs within the injector body, where the fuel pegs are spaced equally and fluidly connected to the vanes, creating a mixing zone that premixes air and fuel before injection into the combustor, reducing NOx emissions by controlling the combustor temperature and residence time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If fuel consumption is increased to reduce emissions, then air-polluting emissions are reduced, but fuel efficiency deteriorates
Solution Approach 1:
The fuel injection system is segmented into multiple fuel vanes with multiple fuel pegs arranged in series, creating multiple injection zones. This segmentation allows for staged fuel injection where fuel is injected at different positions along the flow path, enabling better control of combustion and reduction of emissions without excessive fuel consumption.
Solution Approach 2:
The fuel pegs are arranged to create a premixing zone before the main combustion area. Fuel is injected and mixed with air in advance through the series of fuel pegs, creating a controlled air-fuel mixture before entering the high-temperature combustion zone. This preliminary mixing action allows for more efficient combustion and reduced emissions.
2Object-generated harmful factors
If combustor temperature is maintained below NOx production threshold, then NOx emissions are reduced, but combustion efficiency deteriorates
Solution Approach 1:
The combustion process is segmented into multiple zones created by the series arrangement of fuel pegs. The first fuel peg creates an initial combustion zone, followed by subsequent fuel pegs creating additional combustion zones. This segmentation allows the combustion to occur in stages at different temperatures, preventing excessive temperature rise that would produce NOx while maintaining overall combustion efficiency.
Solution Approach 2:
Different regions of the combustor have different temperature characteristics due to the distributed fuel injection from multiple fuel pegs. The local quality of temperature and fuel-air mixture ratio varies along the flow path, allowing cool regions to prevent NOx formation while hot regions maintain combustion efficiency.
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 fuel injector effectively reduces NOx emissions by optimizing the air-fuel mixture injection, enhancing fuel efficiency and minimizing pollutant production through controlled combustor conditions.
Implementation Method 1
The plurality of fuel pegs are arranged within the plurality of fuel vanes to create a mixing zone
Implementation Method 2
the air-fuel mixture becomes entrained with the main flow of high energy fluid before ignition
Implementation Method 3
the air-fuel mixture becomes entrained with the main flow of high energy fluid before ignition
Data Source
AI summary
A fuel injector is provided, including a fuel injector body, a plurality of fuel vanes, and a plurality of fuel pegs. The injector body includes a manifold and an inlet. The manifold is configured for receiving fuel, and the inlet is configured for receiving air. The fuel vanes are located within the injector body and are positioned in a direction that is generally parallel with a longitudinal axis of the injector body to orient the air flowing from the inlet. The plurality of fuel pegs are fluidly connected to the manifold and are arranged within the plurality of fuel vanes. The plurality of fuel pegs are each spaced at a distance that is about equal between each of the plurality of fuel pegs.