Triple Swirl Gas Turbine Combustor Flame Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gas turbine combustors with single swirlers experience unstable flames due to weak turbulent flow and insufficient fuel-air mixture, leading to imperfect combustion and increased NOx production when handling low and high calorific value gases.
Innovation Solution
A triple swirl gas turbine combustor design featuring concentrically disposed air feeding swirlers with fuel jetting swirl vanes, including a first swirler at the bottom, a second swirler in the middle, and a third swirler at the top, where the second swirler generates a reverse-directed vortex to enhance mixing and turbulence, and lift-off air holes prevent central flame stagnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single swirler is used in the combustor, then the device complexity is reduced, but the turbulent flow intensity is insufficient leading to unstable flame and imperfect combustion
Solution Approach 1:
The single swirler is segmented into three separate swirlers (first, second, and third swirlers) arranged concentrically. Each swirler has its own swirler vanes that can be independently adjusted, allowing each to contribute to turbulent flow generation. This segmentation resolves the contradiction by providing sufficient turbulent flow intensity through multiple components while maintaining reasonable device complexity through their concentric integration.
Solution Approach 2:
The three swirlers are arranged in a nested concentric configuration where the first, second, and third swirlers are positioned one inside another around the central fuel nozzle. This nesting arrangement allows multiple swirlers to occupy compact space without excessive complexity, while collectively generating the required turbulent flow intensity for stable combustion.
2Device complexity
If a single swirler is used in the combustor, then the device complexity is reduced, but insufficient fuel-air mixture leads to increased NOx production
Solution Approach 1:
The combustion air supply is segmented into three separate air streams through the three swirlers, each creating its own vortex and mixing zone. This segmentation allows progressive mixing of fuel and air in stages, ensuring more complete combustion before gases are discharged, thereby reducing NOx formation while maintaining a manageable combustor structure.
Solution Approach 2:
Each swirler is positioned to create localized mixing zones at different radial and axial locations within the combustor. The first swirler near the fuel nozzle creates initial mixing, while the second and third swirlers create subsequent mixing zones. This local quality differentiation ensures thorough fuel-air mixing throughout the combustion chamber, reducing harmful emissions.
3Device complexity
If the second swirler rotates in the same direction as the first and third swirlers, then the device complexity is reduced, but reversing the second swirler direction increases mixing degree and reduces vibration
Solution Approach 1:
The second swirler is configured to rotate in the opposite direction to the first and third swirlers. This inversion creates counter-rotating vortices that enhance turbulent mixing by creating opposing flow patterns. The counter-rotation also balances the rotational forces, reducing net vibration and mechanical stress on the combustor structure while improving combustion efficiency.
4Device complexity
If lift-off air holes are not provided, then the device complexity is reduced, but the flame stays at the center causing incomplete combustion
Solution Approach 1:
Lift-off air holes are extracted as separate functional elements within the burner head, positioned around the central fuel nozzle. These holes extract ambient air and introduce it into the combustion zone, creating upward lift-off flow that prevents flame attachment to the central nozzle. This extraction of lift-off air function improves combustion completeness by ensuring proper flame detachment and mixing.
Solution Approach 2:
The lift-off air holes act as intermediaries that introduce secondary air between the fuel nozzle and the main combustion zone. This intermediary air stream promotes flame lift-off and prevents central flame stagnation, facilitating more complete combustion of the fuel-air mixture while adding minimal structural complexity.
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 triple swirl design improves fuel flexibility, increases combustion efficiency, reduces harmful exhaust gases, and minimizes vibration by enhancing the fuel-air mixture's mixing degree and turbulent flow intensity.
Implementation Method 1
a burner having a plurality of air feeding swirlers with fuel jetting swirl vanes which are concentrically disposed inside a burner head positioned at the upper side of the combustor liner to generate a vortex in the compressed air
Implementation Method 2
mixing degree of fuel-air mixture and intensity of turbulent flow are increased so that combustion efficiency can be increased
Implementation Method 3
The first swirler includes lift-off air holes through which lift-off air is introduced to prevent a flame from staying at the center
Implementation Method 4
a gas turbine is a rotary type heat engine including a combustion chamber provided with a plurality of burners at an upper side and driving turbine with combusted fuel gas at high temperature and high pressure
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed is a triple swirl gas turbine combustor using various fuels such as coal gas, DiMethyl Ether, and waste gas generated in an ironworks in a gas turbine. The triple swirl gas turbine combustor combusts three different fuels simultaneously or individually and various fuels such as LCV gas and HCV gas so that fuel flexibility can be improved. Swirl generated in a second swirler of the triple swirler is reversely jetted to increase a mixing degree of a fuel-air mixture and an intensity of a turbulent flow so that combustion efficiency can be increased, harmful exhaust gas can be reduced and vibration can be reduced.