Trapped Vortex Combustor Steam Injection for Stable Low-Emission Burn
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Solution Overview
Problem
Turbine engines face challenges in balancing low fuel burn and emissions (NOx, nvPM, CO) while maintaining performance and avoiding flameout, particularly due to limitations in steam injection within the combustor.
Innovation Solution
A combustor design incorporating a trapped vortex cavity (TVC) that generates a secondary flame and injects steam downstream, allowing for higher steam-to-air ratios without affecting the primary flame's stability, thereby reducing emissions and fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If steam is injected into the combustor to reduce emissions and fuel consumption, then environmental performance is improved, but flame stability deteriorates and flameout risk increases
Solution Approach 1:
The combustor is divided into distinct functional zones: a primary combustion zone for stable flame establishment and a trapped vortex cavity (TVC) downstream for steam injection and secondary combustion. This spatial segmentation allows steam to be introduced without directly disrupting the primary flame, resolving the contradiction between emission reduction and flame stability.
Solution Approach 2:
The TVC acts as an intermediary structure between the primary combustion zone and the steam injection point. It generates a recirculating vortex that traps combustion products and provides a controlled environment for steam mixing and secondary flame formation, mediating the interaction between steam and primary flame to maintain stability while enabling emission reductions.
2Object-generated harmful factors
If steam-to-air ratio is increased to achieve lower emissions, then environmental performance is improved, but flameout risk increases
Solution Approach 1:
By separating the combustion process into primary flame zone and TVC secondary combustion zone, the system can tolerate higher steam-to-air ratios (up to 60%) in the TVC without causing flameout, as the primary flame remains protected from direct steam exposure.
Solution Approach 2:
The TVC modifies local flow parameters by generating strong recirculation velocities and trapping combustion products, creating a high-temperature environment that maintains flame stability even with high steam concentrations. The vortex structure changes the local velocity, temperature, and concentration parameters to prevent flameout.
3Object-generated harmful factors
If a trapped vortex cavity is added to enable high steam injection, then emission reduction capability is improved, but device complexity increases
Solution Approach 1:
The TVC serves multiple functions simultaneously: it generates vortex flow for steam mixing, traps combustion products for recirculation, provides a secondary combustion zone for CO and unburned hydrocarbon oxidation, and acts as a flow conditioner. This multi-functionality justifies the added structural complexity by delivering multiple performance benefits from a single component.
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 TVC configuration enables up to 60% water-to-air ratios, achieving reduced emissions and fuel consumption while maintaining flame stability, overcoming the limitations of conventional steam injection systems.
Implementation Method 1
A trapped vortex cavity (TVC) that generates a secondary flame
Implementation Method 2
injects steam downstream, allowing for higher steam-to-air ratios without affecting the primary flame's stability
Implementation Method 3
A combustor is arranged in the core section to generate combustion gases for driving a turbine in the core section of the turbine engine
Data Source
AI summary
A combustor includes a combustion chamber having an outer liner and an inner liner and defining a first combustion zone, an annular dome coupled to the outer liner and the inner liner, and a trapped vortex cavity extending from at least one of the outer liner or the inner liner and defining a second combustion zone. A plurality of first mixing assemblies are disposed through the annular dome, and operably inject a first fuel-air mixture into the first combustion zone. A plurality of second mixing assemblies are disposed at the trapped vortex cavity, and operably inject a second fuel-air mixture into the second combustion zone defined in the trapped vortex cavity to produce combustion gases. A steam system includes a steam injector in fluid communication with the trapped vortex cavity. The steam injector operably injects steam into the trapped vortex cavity and the steam mixes with the combustion gases.