Endcover Assembly Fuel Nozzle Vibration Support
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Solution Overview
Problem
In gas turbine combustors, the downstream ends of cantilevered fuel nozzles vibrate during operational cycles, reducing high cycle fatigue design margins due to lack of support, leading to reduced reliability and efficiency.
Innovation Solution
An endcover assembly is introduced, where the fuel nozzle is rigidly connected to an endcover with an inlet flow conditioner and a support plate, providing axial support through mechanical fasteners, thereby stabilizing the fuel nozzle and reducing stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fuel nozzle is left unsupported at the downstream end, then the device complexity is reduced, but the reliability deteriorates due to vibration and reduced fatigue margins
Solution Approach 1:
The support structure is segmented into multiple components: an endcover assembly, a separate support plate, and mounting features. This segmentation allows the support function to be added without requiring a complete redesign of the entire fuel nozzle assembly, thus improving reliability while controlling overall complexity.
Solution Approach 2:
A support plate is introduced as an intermediary component between the fuel nozzle and the endcover assembly. This support plate provides the necessary structural support to reduce vibration and improve fatigue margins while maintaining a relatively simple overall structure through modular design.
2Reliability
If the fuel nozzle is rigidly connected to the endcover, then the reliability is improved through reduced vibration, but the device complexity increases due to additional support structures
Solution Approach 1:
The support plate is merged with the endcover assembly through rigid connection, creating an integrated support structure. This merging provides effective vibration reduction and fatigue protection while minimizing the number of separate components, thus controlling device complexity.
Solution Approach 2:
The endcover assembly serves multiple functions: it provides the end closure for the combustor, supports the fuel nozzle through the support plate, and reduces vibration through rigid connection. This multi-functionality improves reliability without proportionally increasing complexity.
3Reliability
If the downstream end of the fuel nozzle is supported, then the high cycle fatigue design margins are improved, but the manufacturing complexity increases
Solution Approach 1:
The support structure is segmented into discrete components (endcover assembly, support plate, mounting features) that can be manufactured separately using standard manufacturing processes, then assembled together. This segmentation simplifies manufacturing compared to a monolithic support structure while maintaining the necessary fatigue protection.
Solution Approach 2:
The support plate is pre-formed with integrated mounting features and tube holes before assembly. This preliminary preparation of the support structure simplifies the final assembly process and reduces manufacturing complexity while ensuring proper support for the fuel nozzle to improve fatigue margins.
Data Source
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Figure 3
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AI summary
An endcover assembly for a combustor includes an endcover and a fuel nozzle rigidly connected to the endcover. The fuel nozzle includes a plurality of tubes that extends axially through a first plate, a fuel plenum and a second plate where each tube includes an inlet defined upstream of the first plate and an outlet disposed downstream from the second plate. The endcover assembly further includes an inlet flow conditioner having a forward end connected to the endcover and an aft end axially spaced from the forward end. The inlet flow conditioner circumferentially surrounds at least a portion of the fuel nozzle. A support plate is joined to the aft end of the inlet flow conditioner. Each tube of the fuel nozzle extends through a corresponding tube hole defined by the support plate. The fuel nozzle is connected to the support plate.