Segmented Combustor Cap for Thermal Fatigue Mitigation
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Solution Overview
Problem
Current combustor cap designs in industrial gas turbines are prone to thermal fatigue and cracking, leading to repair costs and potential damage to downstream components, and they do not effectively mitigate combustion dynamics instabilities.
Innovation Solution
A segmented combustor cap assembly with radially and tangentially movable cap segments secured to an impingement plate, featuring a collar and connector system that reduces thermal stresses and incorporates a resonator design to dampen combustion acoustic instabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-piece combustor cap design is used, then the structure is simple and easy to manufacture, but the cap is prone to thermal fatigue and cracking under thermal stress
Solution Approach 1:
The combustor cap is divided into multiple segments that can expand and contract independently under thermal stress. This segmentation allows each segment to accommodate thermal expansion without generating excessive stress, thereby preventing thermal fatigue and cracking while maintaining structural integrity during combustion operations
2Reliability
If a segmented combustor cap design is used, then thermal stress and cracking are reduced, but the device complexity increases
Solution Approach 1:
The combustor cap is divided into multiple segments that can expand and contract independently under thermal stress. This segmentation allows each segment to accommodate thermal expansion without generating excessive stress, thereby preventing thermal fatigue and cracking while maintaining structural integrity during combustion operations
Solution Approach 2:
Multiple cap segments are combined with a common support structure that allows independent movement of each segment. The segments are connected through a framework that provides both structural support and freedom of movement, merging the benefits of segmentation with the simplicity of a unified structure
3Device complexity
If traditional combustor cap designs are used, then the structure is straightforward, but combustion dynamics instabilities are not effectively mitigated
Solution Approach 1:
The combustor cap segments are designed to move dynamically in response to combustion pressure fluctuations. This dynamic movement allows the cap structure to interact with combustion dynamics in a way that dampens instabilities and oscillations, improving combustion stability without requiring complex active control systems
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 solution reduces thermal cracking, lowers repair costs, and decreases the amplitude of combustion dynamics, thereby enhancing the reliability and efficiency of gas turbines by minimizing thermal stresses and stabilizing combustion processes.
Implementation Method 1
The plurality of cap segments are secured in such a way as to allow the cap segment edges to be radially and tangentially movable relative to the impingement plate
Implementation Method 2
it would be desirable to utilize the cap as a resonator to thereby decrease the amplitude of combustion dynamics
Data Source
AI summary
A combustor cap is cooperable with an impingement plate in a turbine fuel nozzle and includes a plurality of cap segments independently securable to the impingement plate. The plurality of cap segments are radially and tangentially movable relative to the impingement plate.