Gas Turbine Combustor Flame Lift Control via Swirl Flow
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Solution Overview
Problem
Existing gas turbine combustors face complexity and cost in adjusting the flame lift distance due to variations in fuel radiation heat, requiring cumbersome modifications to balance swirl and straight air quantities.
Innovation Solution
Incorporating an inner diameter enlarging portion at the open end of the premixing tube, which can be adjusted in shape and size to control the flame lift distance by altering the cross-section area of air flow, allowing the flame position to be easily set and changed based on fuel type without extensive structural changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the structure of the premixing tube and swirler is adjusted to set the balance between swirl air quantity and straight air quantity, then the flame lift distance can be controlled to prevent thermal damage, but the adjustment process becomes very complicated and time-consuming
Solution Approach 1:
The invention separates the air flow control function into two independent components: a swirler that generates swirl flow and a flow rate adjustment mechanism that controls straight air flow. This segmentation allows each component to be adjusted independently, simplifying the overall adjustment process while maintaining reliable flame position control to prevent combustion cylinder damage.
2Length of moving object
If the swirl air quantity is increased and straight air quantity is reduced to shorten the lift distance, then the flame position changes, but extensive modification of the combustor structure is required
Solution Approach 1:
The invention introduces a flow rate adjustment mechanism that enables dynamic control of the straight air flow rate without requiring structural modifications to the combustor. This allows the flame lift distance to be adjusted dynamically by changing operational parameters rather than manufacturing new components, significantly improving ease of manufacture and adaptability.
3Adaptability or versatility
If the combustor structure is modified to adapt to different fuel types with varying radiation heat, then the flame lift distance can be optimized, but the process becomes far more complicated and costly than manufacturing a new combustor
Solution Approach 1:
The invention enables adaptation to different fuel types by changing operational parameters (swirler speed, straight air flow rate) rather than modifying the physical structure. The flow rate adjustment mechanism allows operators to optimize flame lift distance for various fuels with different radiation heat characteristics, providing high adaptability without the complexity and cost of structural modifications or new combustor manufacturing.
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
Enables flexible adjustment of the flame lift distance to match varying fuel radiation heat, preventing combustion cylinder deterioration and simplifying the process of adapting to different fuels by modifying the inner diameter enlarging portion rather than the entire combustor structure.
Implementation Method 1
air flowing inside through holes 25 in a peripheral wall surface of the premixing tube generates a swirl flow that surrounds the axial flow within the combustor
Implementation Method 2
The injected fuel is atomized by air from a circumferential air passage 22 that surrounds the nozzle portion
Implementation Method 3
the radiation heat of the flame varies with type of the fuel in use... prevent deterioration in durability of the combustion cylinder by the heat of the flame
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A gas turbine combustor (1) includes a combustion cylinder (2) and a premixing tube (3). A protruding wall (7) of the premixing tube has an inner diameter enlarging portion (10) with a chamfer (11) at its open end. A swirl flow in the premixing tube is guided outward along the chamfer (11), and the cross-section area of a straight flow in the premixing tube is expanded to lower the flow velocity, which shortens the distance between a flame in the combustion cylinder and the inner diameter enlarging portion (lift distance). When using the fuel with high heat radiation upon combustion, the inner diameter enlarging portion is replaced with the one having a smaller chamfer. The cross-section area of the straight flow is reduced to increase the flow velocity, making the lift distance long. This prevents damage to the combustion cylinder owing to the intensified heat radiation. The flame lift position retained in the combustion cylinder may be easily set and changed.