Combustor Casing Ring Plate Dampener Mitigating Dynamics
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Solution Overview
Problem
Combustion dynamics in Dry Low NOx, Dry Low Emissions, and Lean Pre Mix combustors lead to significant pressure fluctuations due to lean fuel/air ratios, resulting in thermo-acoustic instabilities, which existing solutions like external dampeners and active fuel flow control have not adequately addressed.
Innovation Solution
A steam injection combustor casing with a ring plate that reduces the casing volume and acts as an integrated dampener, featuring inwardly protruding walls or lobes to mitigate low-frequency combustion dynamics, eliminating the need for external dampeners and allowing for retrofitting or integral formation within the casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external dampeners or active fuel flow control are used to mitigate combustion dynamics, then combustion stability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The dampening function is merged with the combustor casing structure by integrating a ring plate with inwardly protruding wall portions directly into the casing. This eliminates the need for separate external dampeners and reduces system complexity while maintaining combustion stability through the dampening effect of the integrated structure.
Solution Approach 2:
The combustor casing itself provides the dampening function through its integrated ring plate structure. The casing serves dual purposes: containing the combustion process and mitigating combustion dynamics through its geometric features, eliminating the need for additional active control systems.
2Reliability
If external dampeners are added to the combustor system, then low-frequency combustion dynamics are reduced, but ease of manufacture decreases
Solution Approach 1:
The dampening functionality is combined with the combustor casing as a single integrated component. The ring plate with inwardly protruding wall portions is formed as part of the casing structure, allowing for simplified manufacturing processes and eliminating the need for separate dampener assemblies.
Solution Approach 2:
The combustor casing is designed to perform multiple functions: containing the combustion process, providing structural support, and mitigating low-frequency combustion dynamics through its integrated ring plate geometry. This multi-functionality simplifies manufacturing by reducing the total number of components.
3Reliability
If the combustor casing volume is reduced by adding internal structures, then dampening effectiveness is improved, but the available combustion chamber volume decreases
Solution Approach 1:
The dampening structure utilizes the radial dimension by adding inwardly protruding wall portions that extend from the casing wall toward the combustion chamber center. This approach provides dampening effectiveness without significantly reducing the axial length or overall volume of the combustion chamber, thereby maintaining combustion stability while preserving chamber volume.
Solution Approach 2:
The ring plate with inwardly protruding wall portions is strategically positioned at specific locations within the combustor casing to provide dampening where it is most effective. The discontinuous or segmented nature of the wall portions allows for localized dampening action that minimizes impact on overall chamber volume while addressing combustion dynamics issues.
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 ring plate effectively reduces low-frequency combustion dynamics, enhancing operational stability and manufacturing efficiency by integrating the dampening function within the combustor casing, thereby addressing the instability issues in these advanced combustion systems.
Implementation Method 1
a ring plate configured to reduce the volume of the casing. The ring plate within the casing acts as a dampener to reduce low frequency combustion dynamics
Implementation Method 2
The ring plate carries discontinuous or segmented inwardly protruding wall portions or lobes of various shapes
Data Source
Figure 1
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Figure 5
AI summary
A dampener or resonator is provided within a combustor casing (12) to mitigate combustion dynamics. The combustor casing (12) head end volume is reduced by the resonator to mitigate combustion dynamics. The resonator is formed by a ring shaped plate that carries a continuous inwardly protruding wall (14) or segmented inwardly protruding wall portions. The resonator can be a stand alone part that is inserted into the combustor casing (12) or it can be integrally formed with the combustor casing (12).