Gas Turbine Combustor Swirl Plate Grooves Flame Stability
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Solution Overview
Problem
Gas turbine combustors face challenges in achieving stable combustion and low NOx emission, particularly due to fluctuations in air and fuel flow rates which can lead to unstable combustion and increased NOx production, especially when handling fuels with high hydrogen content.
Innovation Solution
The design incorporates multiple burners with fuel nozzles and air holes arranged in concentric circles, featuring a swirl plate with grooves to stabilize flames and prevent NOx formation by ensuring proper mixing and flame adherence to the central region while preventing flame adhesion to the peripheral region, thereby maintaining stable combustion and reducing NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If premix combustion is employed to reduce NOx emission, then NOx emission is reduced, but the possibility of flashback increases
Solution Approach 1:
The burner is divided into multiple burners (at least two) arranged in parallel, with each burner having its own flame stabilization means. This segmentation allows independent control of flame stabilization for each burner, preventing flashback while maintaining premix combustion benefits for NOx reduction.
Solution Approach 2:
Different regions of the burner are provided with different flame stabilization structures. The flame stabilization means are positioned at specific locations where flashback is most likely to occur, providing localized protection while maintaining overall premix combustion efficiency.
2Productivity
If air and fuel flow rates are increased to meet higher load demands, then productivity is improved, but combustion stability deteriorates
Solution Approach 1:
The burner system is segmented into multiple independent burners, each with its own flame stabilization means. This allows the system to handle higher total load while each individual burner maintains stable combustion through its dedicated stabilization structure, preventing combustion instability even at high load conditions.
3Use of energy by moving object
If fuels with high hydrogen content are used to increase energy density, then use of energy is improved, but flashback resistance worsens
Solution Approach 1:
The burner is divided into multiple burners with independent flame stabilization means, allowing high hydrogen content fuels to be burned efficiently while the stabilization structures prevent flashback propagation that is more likely with high-combustion-speed fuels.
Solution Approach 2:
Flame stabilization means are positioned at specific locations within the burner system where flashback is most likely to initiate, providing localized protection that is particularly important when using high hydrogen content fuels with higher combustion speeds.
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 achieves stable combustion in the central region and low NOx combustion in the peripheral region, enhancing the overall performance and reducing the risk of flashback, thus addressing the instability and emission issues in gas turbine combustors.
Implementation Method 1
the central part of the burner secures combustion stability by forming a swirl flow
Implementation Method 2
the gas turbine combustor is capable of rapidly mixing fuel and air together in an extremely short distance compared to gas turbine combustors employing conventional premix combustion methods
Implementation Method 3
a combustion chamber which is arranged downstream of the burner to burn the air-fuel mixture
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In a perforated coaxial jet burner implemented by a lot of air-fuel coaxial jets, a swirl plate (33) as an end face of the burner on the combustion chamber's side has a lot of air holes for supplying unburned premixed gas of fuel and air to the combustion chamber. Grooves (36) are formed downstream of the air holes of the swirl plate. Adhesion of flame to the swirl plate is inhibited by feeding part of the unburned premixed gas to the grooves. Further, the width of each remaining part (37) between adjacent grooves is set at several millimeters that is approximately equal to the flame quenching distance, by which adhesion of flame to the remaining parts is also prevented. With this configuration, both stable combustion and low NOx combustion can be achieved irrespective of the load condition.