Combustor Cap Retention System for Gas Turbine Maintenance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current combustor cap assemblies in gas turbines face challenges in directing air flow for combustion and cooling while maintaining structural integrity under high vibration loads, and they are complex and costly to install, remove, and maintain due to permanent joints.
Innovation Solution
A retention system for a combustor cap module that includes a cap face assembly with a cooling plate, a cylindrical sleeve, a support plate, a retaining ring, and a spring plate, allowing for easy assembly and disassembly using hand tools, and providing structural support and alignment of fuel nozzles without obstructing air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If permanent joints (welded connections) are used between combustor cap components, then structural stability and strength are improved, but assembly and disassembly time increases significantly and maintenance complexity increases
Solution Approach 1:
The combustor cap assembly is divided into modular components (cap body, cooling plates, fuel nozzle assemblies) that can be independently assembled and disassembled. The retention system uses a retaining ring and spring plate mechanism that allows the cap face assembly to be segmented into removable sections, eliminating the need for permanent welding while maintaining structural integrity during operation.
Solution Approach 2:
The retention system transitions from static permanent joints to a dynamic fastening mechanism. The spring plate provides elastic retention force that holds components together during operation but allows for controlled disassembly when needed, enabling the system to adapt between operational stability and maintenance accessibility.
2Reliability
If permanent joints are used to maintain structural integrity under high vibration loads, then reliability under vibration is improved, but ease of repair and maintenance deteriorates
Solution Approach 1:
The assembly is segmented into modular units that can be independently accessed and replaced. The cap face assembly can be removed as a unit or in sections without affecting the entire combustor cap structure, allowing targeted maintenance of specific components like fuel nozzles or cooling plates while maintaining overall structural integrity.
Solution Approach 2:
The design allows individual components such as fuel nozzle assemblies or cooling plates to be easily removed, inspected, and replaced independently. Worn or damaged parts can be discarded and replaced without affecting other components, significantly reducing maintenance time and complexity while maintaining reliability.
3Strength
If a robust retention system is implemented to withstand turbine and combustion frequencies, then structural robustness is improved, but device complexity increases
Solution Approach 1:
The retention function is merged with the existing cap face assembly structure. The retaining ring and spring plate are integrated into the cap face design, combining the retention mechanism with the structural components rather than adding separate, complex fastening systems. This integration maintains robustness while minimizing additional complexity.
Solution Approach 2:
The spring plate serves multiple functions: it provides elastic retention force to secure the cap face assembly, accommodates thermal expansion and vibration, and facilitates easy removal when bolts are loosened. This multi-functionality reduces the need for additional specialized components, keeping the system relatively simple while achieving robust performance.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A combustor cap module (120) is provided with a retention system to facilitate assembly and disassembly. The combustor cap module (120) further includes a cap face assembly (80) having a cooling plate (82); a cylindrical sleeve (84) including a connecting surface (85) for attaching the cap face assembly (80) to the retention assembly (100); and a coupling member (60) mounted in a downstream fuel nozzle opening (88) in the cooling plate (82). The retention system (100) includes a support plate (50) having an inner panel that defines an upstream fuel nozzle opening (56). The coupling member (60) extends through the upstream fuel nozzle opening (56), such that its upstream end extends upstream of the support plate (50). A retaining ring at least partially encircles the upstream end of the coupling member (60) and is engaged by a spring plate that is removably secured to the support plate (50) at multiple locations. A method for assembling a combustor cap module (120) is also provided.