Intermediate Structural Frame for Gas Turbine Combustor Cap Stability
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Solution Overview
Problem
Existing gas turbine combustor cap assemblies are vulnerable to loads transferred between pre-mix tubes and the effusion plate, leading to dynamic displacements and potential fatigue damage due to combustion-induced vibrations, causing pre-mix tube liberation and downstream turbine damage.
Innovation Solution
A structural frame is introduced that stabilizes pre-mix tubes to each other and the surrounding support ring, reducing relative displacements and loads on the effusion plate by using an intermediate structural frame with encirclements and flanges to provide mechanical interconnection and support, thereby enhancing the stability and dynamic capability of the combustion system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pre-mix tubes are supported in a cantilevered fashion from a primary feed structure, then ease of manufacture is improved, but stability deteriorates causing excessive relative displacements and dynamic displacements
Solution Approach 1:
The support structure is segmented into multiple levels: a primary feed structure for ease of manufacture, an intermediate structural frame with encirclements for stability, and individual tube supports. This segmentation allows each component to optimize its function while the overall system achieves both manufacturability and stability.
Solution Approach 2:
An intermediate structural frame is introduced between the primary feed structure and the pre-mix tubes. This intermediary component transfers and distributes loads, preventing excessive relative displacements while maintaining the ease of manufacture of the primary feed structure.
2Device complexity
If pre-mix tubes are cantilevered without additional support, then device complexity is reduced, but strength deteriorates leading to fatigue damage and tube liberation
Solution Approach 1:
The support system is divided into multiple functional segments: the primary feed structure, the intermediate structural frame with encirclements, and individual tube supports. This segmentation provides strength where needed without unnecessarily complicating the entire device.
Solution Approach 2:
Additional support structures are applied locally at critical locations where pre-mix tubes experience high stresses and vibrations. The intermediate structural frame provides localized reinforcement without requiring comprehensive strengthening of the entire assembly.
3Ease of operation
If pre-mix tubes are freely positioned, then ease of operation is improved, but reliability deteriorates due to dynamic displacements and loads on the effusion plate
Solution Approach 1:
The intermediate structural frame with encirclements provides dynamic support that adapts to operational conditions. The frame stabilizes pre-mix tubes during combustion-induced vibrations while allowing necessary thermal expansion and movement, maintaining reliability without restricting operational flexibility.
Data Source
AI summary
An intermediate support frame (68) that spans an inner diameter of a support ring (48) of a gas turbine combustor cap assembly (24) at a position intermediate the length of the support ring. The intermediate support frame may have a central encirclement (72) that receives a central fuel pre-mix tube (44) of the combustor cap assembly, and may further have a circular array of outer stabilization rings (70) that each receive a respective outer pre-mix tube (42). The central pre-mix tube may be affixed to the central encirclement (72), for example by welding. The outer pre-mix tubes may be slidably engaged in the outer stabilization rings (70), providing lateral stability while allowing differential thermal expansion. The intermediate support frame may have holes (74) for coolant passage, and perimeter tabs (76) for attachment to the support ring (48).