Gas Turbine Combustor Nozzle Swirling Flow Control
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Solution Overview
Problem
Conventional gas turbine combustors experience unstable combustion and increased NOx generation due to fluctuations in air flow from the pilot nozzle, leading to potential damage to the nozzle and inefficient turbine operation.
Innovation Solution
A nozzle design with a swirling force application unit, guide portions at the inner air passage outlet, and fuel injection nozzles at the nozzle tips, which stabilizes the air flow and maintains a proper fuel-air ratio, reducing temperature rises and NOx production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air flow amount from the pilot nozzle is increased, then the combustion stability is improved, but the velocity distribution within the pilot cone changes greatly causing combustion instability
Solution Approach 1:
The patent introduces a swirling flow generation unit that changes the flow parameters of air injected from the inner air passage. By converting axial flow to swirling flow, the velocity distribution is stabilized even when air flow amount varies, resolving the contradiction between combustion stability and velocity distribution stability
Solution Approach 2:
The swirling flow generation unit acts as an intermediary between the air injection system and the combustion zone. It mediates the air flow to create a controlled swirling pattern that stabilizes combustion while maintaining consistent velocity distribution
2Temperature
If the air flow amount from the pilot nozzle is decreased, then the cooling effect is improved, but the temperature increases causing nozzle damage and increased NOx generation
Solution Approach 1:
By changing the flow parameters through swirling flow generation, the patent achieves effective cooling and temperature control without simply increasing air flow amount. The swirling flow pattern enhances heat transfer efficiency, preventing nozzle damage and reducing NOx generation while maintaining appropriate cooling
3Device complexity
If conventional pilot nozzle design is used, then the structure is simple, but the air flow velocity distribution fluctuates causing unstable combustion
Solution Approach 1:
The swirling flow generation unit is introduced as an intermediary component between the simple nozzle structure and the combustion zone. This addition maintains structural simplicity while significantly improving combustion stability through controlled swirling flow
Solution Approach 2:
The patent makes a minimal structural modification by adding guide surfaces that change flow parameters. This simple parameter change from axial to swirling flow achieves stable combustion without greatly complicating the nozzle structure
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 achieves stable combustion, prevents nozzle damage, and reduces NOx generation, thereby improving turbine efficiency and operational stability.
Implementation Method 1
the air injected toward the front side of the nozzle main body from the cover ring through the inner air passage becomes a swirling flow by the swirling force application unit
Data Source
Figure 1-1~1-2
Figure 2
Figure 3
AI summary
A pilot nozzle, a gas turbine combustor and a gas turbine are provided with: a nozzle main body (71) having a fuel passage way (72); a covering (75) that forms an interior air passageway (78) by being positioned so as to form a predetermined gap in the external section of the front edge of the peripheral portion of a nozzle main body (71) and is capable of spraying air towards the front end of the nozzle main body (71); a plurality of nozzle tips (80) having a fuel spray nozzle (81) communicating with the fuel passage way (72) and is attached to the edge section of the covering (75) in a circumferential direction at predetermined intervals and capable of spraying fuel to the exterior portion of the blast air from the interior air passageway (78); and a torque add-on applicator that adds torque to the air passing through the interior air passageway (78). Thus, the air quantity to be cooled and the velocity distribution within the pilot cone can be controlled to achieve a steady combustion process.