Rich-Quench-Lean Combustor Assembly for NOx Reduction
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Solution Overview
Problem
Traditional gas turbine engine combustors produce high peak temperatures and undesirable amounts of NOx due to stoichiometric combustion, leading to inefficiencies and environmental concerns.
Innovation Solution
A combustor assembly with a rich-quench-lean configuration, featuring a pre-mix fuel nozzle and two-stage quench air jets, achieves initial rich combustion followed by lean combustion, reducing NOx emissions through efficient fuel-air mixing and air introduction in a secondary combustion zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stoichiometric combustion is used with equivalence ratio of 1:1, then complete fuel combustion is achieved, but high peak temperatures are produced leading to high NOx formation
Solution Approach 1:
The combustion process is segmented into multiple zones with different equivalence ratios: a first combustion zone with rich combustion (equivalence ratio > 1) and a second combustion zone with lean combustion (equivalence ratio < 1). This segmentation allows complete fuel combustion while controlling peak temperatures to reduce NOx formation.
Solution Approach 2:
Different regions of the combustion chamber are assigned different local qualities in terms of equivalence ratio. The first combustion zone has a rich mixture (higher fuel concentration) while the second combustion zone has a lean mixture (higher air concentration). This local differentiation enables simultaneous achievement of complete combustion and temperature control.
2Object-generated harmful factors
If rich combustion is used in the first combustion zone, then peak temperatures are reduced lowering NOx formation, but complete fuel combustion may not be achieved
Solution Approach 1:
The combustion chamber is divided into two sequential combustion zones. The first zone performs rich combustion to limit peak temperatures, while the second zone performs lean combustion to complete the fuel oxidation. This sequential segmentation ensures both temperature control and complete combustion.
Solution Approach 2:
The rich combustion in the first zone is performed as a preliminary action to consume the majority of fuel while controlling temperature. The subsequent lean combustion in the second zone then completes the combustion process. This preliminary rich combustion phase prevents excessive temperature rise before final fuel consumption.
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 configuration minimizes NOx formation by managing combustion temperatures and ensuring complete fuel combustion, resulting in a more efficient and environmentally friendly operation of the gas turbine engine.
Implementation Method 1
pre-mix fuel nozzle... achieves initial rich combustion followed by lean combustion, reducing NOx emissions through efficient fuel-air mixing
Implementation Method 2
Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases
Implementation Method 3
two-stage quench air jets, achieves initial rich combustion followed by lean combustion, reducing NOx emissions through efficient fuel-air mixing and air introduction
Data Source
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AI summary
A rich-quench-lean combustor assembly for a gas turbine engine includes a fuel nozzle and a dome, the fuel nozzle attached to the dome. The combustor assembly additionally includes a liner attached to or formed integrally with the dome, the liner and the dome together defining at least in part a combustion chamber. Additionally, the liner extends between a forward end and an aft end. The liner includes a plurality of quench air jets positioned between the forward end and aft end and defines a forward section extending from the quench air jets to the dome. The dome and the forward section of the liner are configured to be cooled substantially by one or both of impingement cooling or convective cooling.