Trapped Vortex Combustor for High Steam Injection Stability
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Solution Overview
Problem
Turbine engines face challenges in balancing low fuel burn and low emissions (NOx, nvPM, CO) while maintaining performance and avoiding flameout, with existing steam injection systems limited by flameout at high steam-to-air ratios.
Innovation Solution
A turbine engine with a trapped vortex cavity (TVC) that generates a secondary flame and injects steam downstream, allowing higher steam-to-air ratios up to 60% without sacrificing operability, reducing emissions and specific fuel consumption (SFC) while ensuring flame stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If steam is injected into the combustion chamber to reduce emissions and fuel consumption, then emissions and specific fuel consumption are reduced, but flameout occurs at high steam-to-air ratios
Solution Approach 1:
The combustion chamber is segmented into a main combustion zone and a trapped vortex cavity (TVC). The TVC is a separate region that traps and recirculates hot gases, creating a protected zone that stabilizes the flame. This segmentation allows steam to be injected into the main combustion zone without directly extinguishing the flame, as the TVC provides a stable ignition source that prevents flameout even at high steam-to-air ratios up to 60%.
2Object-generated harmful factors
If steam injection rate is increased to enhance emission reduction, then emissions are reduced, but flameout occurs
Solution Approach 1:
The trapped vortex cavity acts as an intermediary between the steam injection and the flame. It recirculates hot gases that serve as a buffer, protecting the flame from the cooling and diluting effects of steam injection. This intermediary mechanism allows high steam injection rates to reduce emissions while the recirculated hot gases maintain flame stability and prevent flameout.
3Use of energy by moving object
If higher steam-to-air ratios are used to reduce specific fuel consumption, then fuel efficiency improves, but operability is compromised due to flameout
Solution Approach 1:
The trapped vortex cavity performs preliminary action by pre-heating and recirculating combustion gases before they interact with the incoming air-steam mixture. This pre-conditioning of the gases creates a more favorable environment for combustion, allowing the engine to operate with high steam-to-air ratios (up to 60%) without flameout, thereby maintaining both fuel efficiency and operability across a wider range of operating conditions.
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 reduced emissions and SFC by injecting steam away from the main combustion zone, stabilizing flames and avoiding flameout, achieving up to 60% water-to-air ratios for enhanced performance.
Implementation Method 1
A trapped vortex cavity (TVC) that generates a secondary flame
Implementation Method 2
injects steam downstream, allowing higher steam-to-air ratios up to 60% without sacrificing operability
Implementation Method 3
combustor arranged in the core section to generate combustion gases for driving a turbine
Data Source
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AI summary
A combustor (200, 300, 400, 50, 600, 700, 800, 900, 1000, 1100, 1200) that includes a combustion chamber (202, 1002) having an outer liner (204, 1004) and an inner liner (206, 1006) and defining a first combustion zone (202a, 1002a), an annular dome (210, 1010, 1110) coupled to the outer liner (204, 1004) and the inner liner (206, 1006), and a trapped vortex cavity (230, 330, 430, 530, 630, 730, 830, 930, 1030, 1230) extending from at least one of the outer liner (204, 1004) or the inner liner (206, 1006) and defining a second combustion zone (202b, 302b, 402b, 502b, 602b, 702b, 802b, 902b, 1002b, 1202b). A plurality of first mixing assemblies (212, 912, 1012, 1112) are disposed through the annular dome (210, 1010, 1110), and operably inject a first fuel-air mixture into the first combustion zone (202a, 1002a). A plurality of second mixing assemblies (220, 420, 620, 820, 920, 1020) are disposed through the outer liner (204, 1004) or the inner liner (206, 1006) at the trapped vortex cavity (230, 330, 430, 530, 630, 730, 830, 930, 1030, 1230), and operably inject a second fuel-air mixture into the second combustion zone (202b, 302b, 402b, 502b, 602b, 702b, 802b, 902b, 1002b, 1202b) to produce combustion gases (66). A steam system (90) includes a steam injector (244, 344, 544, 744, 944, 1044, 1144, 1244) in fluid communication with the trapped vortex cavity (230, 330, 430, 530, 630, 730, 830, 930, 1030, 1230). The steam injector (244, 344, 544, 744, 944, 1044, 1144, 1244) operably injects steam (69) into the trapped vortex cavity (230, 330, 430, 530, 630, 730, 830, 930, 1030, 1230) and the steam (69) mixes with the combustion gases (66).