Turbine Combustor Radial Axial Staging Trapped Vortex Cavity
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Solution Overview
Problem
Current turbine engine combustor designs face challenges in balancing NOx, nvPM, and CO2 emissions across various power operations, with traditional designs failing to optimize stoichiometry and fuel placement effectively, leading to increased emissions at higher temperatures and longer residence times.
Innovation Solution
A multi-staged combustor system incorporating radial and axial staging with a trapped vortex cavity (TVC) that injects combustion gases downstream, providing a nested flame structure and improved fuel-air mixing, allowing for leaner combustion and reduced NOx emissions through radial and axial fuel staging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional combustor designs are used, then structural simplicity is maintained, but NOx emissions increase due to higher temperatures and longer residence times
Solution Approach 1:
The combustor is divided into multiple combustion zones with distinct fuel-air mixing characteristics. The first combustion zone operates with a first equivalence ratio while the second combustion zone operates with a second equivalence ratio, allowing separate optimization of each zone to reduce overall NOx emissions while managing complexity through modular design
Solution Approach 2:
Different regions of the combustor are given different fuel-air equivalence ratios tailored to local requirements. The first combustion zone uses a richer mixture for stability while the second zone uses a leaner mixture for lower temperatures and reduced NOx formation, applying local quality variations to solve the emissions-complexity contradiction
2Productivity
If fuel-air mixing is optimized for complete combustion, then combustion efficiency improves, but residence time increases leading to higher NOx emissions
Solution Approach 1:
The combustion process is segmented into two distinct zones with different equivalence ratios. The first zone ensures complete combustion of the fuel for high efficiency, while the second zone with a leaner mixture completes the oxidation process quickly at lower temperatures, reducing NOx formation despite extended total residence time
Solution Approach 2:
The equivalence ratio parameter is changed between combustion zones to optimize both combustion efficiency and NOx emissions. By transitioning from a richer first zone to a leaner second zone, the system maintains high combustion efficiency while reducing peak temperatures and NOx formation rates
3Object-generated harmful factors
If stoichiometry is optimized for low emissions, then NOx emissions decrease, but combustion stability deteriorates
Solution Approach 1:
Combustion stability is ensured in the first combustion zone with a richer equivalence ratio that provides robust flame holding, while the second combustion zone operates with a leaner equivalence ratio for low NOx emissions. The segmented approach allows each zone to be optimized for its primary function, maintaining overall stability while reducing emissions
Solution Approach 2:
The combustor applies different local quality characteristics to different zones: the first zone has a richer fuel-air mixture for stability and flame anchoring, while the second zone has a leaner mixture for emissions control. This local differentiation resolves the contradiction between stability and emissions by allowing each region to perform its specialized function
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 achieves significant reductions in NOx emissions (over 50% below regulatory limits) across the entire mission cycle of a turbine engine, while maintaining efficient combustion and operability, by optimizing fuel-air ratios and residence times through the combined radial and axial staging with the TVC.
Implementation Method 1
A multi-staged combustor system incorporating radial and axial staging with a trapped vortex cavity (TVC) that injects combustion gases downstream
Implementation Method 2
A combustor arranged in the core section to generate combustion gases for driving a turbine of the turbine engine
Data Source
AI summary
A combustor for a turbine engine includes a combustion chamber including an outer liner and an inner liner, an annular dome, and a trapped vortex cavity (TVC) downstream of the annular dome. A plurality of first mixing assemblies are disposed through the annular dome and include a pilot mixer and a first main mixer. The pilot mixer injects a pilot mixer fuel-air mixture axially into a first combustion zone, and the first main mixer injects a first main mixer fuel-air mixture radially into the first combustion zone. A plurality of second mixing assemblies are disposed at the TVC axially aft of the first mixing assemblies and include a second main mixer. The second main mixer injects a second main mixer fuel-air mixture into a second combustion zone defined by the TVC and axially aft of the first combustion zone. The TVC injects the combustion gases into the combustion chamber.