Gas Turbine Combustor Small Holes Flashback Prevention
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Solution Overview
Problem
Gas turbine combustors face challenges in reducing nitrogen oxide (NOx) emissions and preventing flashback while heating combustion gas to high temperatures, and there is a risk of particulate matter adhesion to the burner, which can lead to overheating and structural damage.
Innovation Solution
A lean-combustion gas turbine combustor design featuring a tubular liner and a burner with an air hole plate and fuel nozzles forming concentric annular lines, including small holes with smaller diameters than the air holes, positioned in the innermost annular line to prevent particulate matter adhesion and improve structural reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the combustion air temperature is raised and fuel concentration in the premixer is increased to heat combustion gas to high temperature, then power generation efficiency is improved, but the risk of flashback toward the upstream of the combustion chamber increases
Solution Approach 1:
The air hole plate is segmented into multiple concentric annular lines with different hole diameters. The innermost annular line has small holes (0.5-2mm diameter) that prevent flashback, while outer annular lines have larger air holes (3-10mm diameter) that provide sufficient airflow for high-temperature combustion. This segmentation allows simultaneous achievement of high combustion temperature and flashback prevention.
Solution Approach 2:
Different regions of the air hole plate are assigned different hole diameters based on local requirements. The central innermost region has small holes optimized for flashback prevention, while outer regions have larger holes optimized for combustion efficiency. This local differentiation resolves the contradiction between high temperature combustion and flashback risk.
2Stability of the object's composition
If diffusion combustion is used to achieve good combustion stability, then combustion stability is improved, but local high temperature flames are generated causing increased NOx emissions
Solution Approach 1:
The combustion process is segmented into multiple stages through concentric annular lines with different hole diameters. The innermost small holes create a controlled premixed combustion zone that prevents local high-temperature formation, while outer larger holes provide additional airflow. This segmentation maintains combustion stability while distributing heat more evenly to reduce NOx emissions.
Solution Approach 2:
The hole diameter parameter is changed across different annular lines to control combustion characteristics. Small holes in the innermost line create a leaner mixture with lower peak temperatures, reducing NOx formation, while still maintaining overall combustion stability through the combined effect of all annular lines.
3Object-generated harmful factors
If premixed combustion is used to reduce NOx emissions, then NOx emissions are reduced, but flashback risk increases when combustion air temperature is raised
Solution Approach 1:
The air hole plate is divided into concentric annular lines with progressively different hole diameters. The innermost small holes (0.5-2mm) act as a flashback barrier while the outer larger holes (3-10mm) provide sufficient airflow for efficient combustion. This segmentation allows premixed combustion to achieve low NOx emissions without excessive flashback risk.
4Temperature
If a wall surface without air holes is provided in the central section of the air hole plate, then particulate matters can adhere to the wall surface for cooling, but the burner may overheat if particulate matters are ignited and downstream structures may be damaged if particulate matters fall off
Solution Approach 1:
Instead of creating a solid wall surface without air holes, the patent segments the central region into multiple small holes arranged in the innermost annular line. This segmentation prevents the formation of a particulate matter accumulation surface while still providing cooling airflow to the burner, eliminating the risk of overheating and downstream damage from ignited or falling particulate matters.
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 design effectively suppresses particulate matter adhesion to the burner, enhancing structural reliability and reducing the risk of overheating and damage, while maintaining low NOx emissions and stable combustion.
Implementation Method 1
a plurality of small holes having opening diameters smaller than opening diameters of the air holes are provided through the air hole plate such that the plurality of small holes are positioned in an inner area of an innermost annular line of the air holes
Implementation Method 2
a plurality of fuel nozzles that are arranged on a side opposite to the combustion chamber with the air hole plate being sandwiched therebetween, the plurality of fuel nozzles each injecting a fuel toward a corresponding air hole
Implementation Method 3
a plurality of small holes having opening diameters smaller than opening diameters of the air holes are provided through the air hole plate such that the plurality of small holes are positioned in an inner area of an innermost annular line of the air holes
Data Source
AI summary
Adhesion of particulate matters to the burner accompanying combustion in a lean-combustion gas turbine combustor is suppressed, and the structural reliability is improved. In a gas turbine combustor including: a tubular liner that forms a combustion chamber; and a burner including an air hole plate that is arranged at an inlet of the liner and includes a plurality of air holes for guiding compressed air to the combustion chamber, and a plurality of fuel nozzles that are arranged on a side opposite to the combustion chamber with the air hole plate being sandwiched therebetween, the plurality of fuel nozzles each injecting a fuel toward a corresponding air hole, the air holes and the fuel nozzles forming a plurality of concentric annular lines, a plurality of small holes having opening diameters smaller than those of the air holes are provided through the air hole plate such that the plurality of small holes are positioned in an inner area of an innermost annular line of the air holes.