Gas Turbine Burner Insert Edge Web Stiffening
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Solution Overview
Problem
Gas turbine combustor burner inserts experience high-frequency oscillations due to pressure fluctuations, leading to reduced service life and uneven cooling air distribution, which results in inefficiencies and increased pollutant emissions.
Innovation Solution
A burner insert design featuring an edge web that projects beyond the cold side with crenellations to create defined openings for cooling air flow, increasing natural frequencies and ensuring a uniform gap, thereby reducing vibration loads and optimizing cooling air distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ribs and support screws are added to stiffen the burner insert, then vibration resistance improves, but device complexity increases and uneven gaps form along the peripheral edge
Solution Approach 1:
The edge web is segmented into multiple sections with varying heights, creating a stepped profile that provides stiffening at critical locations while maintaining simplicity in the overall structure. This segmentation allows the edge web to act as both a support element and a vibration damping structure without requiring additional separate components.
Solution Approach 2:
The edge web combines multiple functions into a single structural element: it provides stiffening to reduce vibrations, creates a uniform gap for consistent cooling air flow, and serves as the primary support interface with the support structure. By merging these functions into one component, the design eliminates the need for separate ribs and support screws, reducing overall device complexity.
2Strength
If support screws and ribs are used together, then support strength improves, but static overdetermination occurs and manufacturing precision requirements increase
Solution Approach 1:
The design extracts and eliminates the support screws from the system, retaining only the edge web as the support mechanism. This removal of the redundant support element eliminates static overdetermination and allows the gap between the burner insert and support structure to be uniformly controlled by the edge web geometry alone, significantly improving manufacturing precision requirements.
3Reliability
If the edge web is made taller to increase rigidity, then natural frequency increases, but cooling air flow is interrupted
Solution Approach 1:
The edge web features local variations in height, with taller sections at specific locations providing enhanced rigidity and natural frequency, while shorter sections maintain open passages for cooling air flow. This local differentiation of geometry allows the structure to achieve both increased rigidity and uninterrupted cooling air flow simultaneously.
Solution Approach 2:
The solution moves from a two-dimensional flat edge web to a three-dimensional stepped profile, utilizing vertical dimensionality to create both structural stiffening elements and fluid flow passages. The stepped geometry allows cooling air to flow through vertical passages while the horizontal portions provide the necessary rigidity and gap uniformity.
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 design enhances the rigidity of the burner insert, reduces cooling air oversupply, decreases pollutant emissions, and increases turbine inlet temperatures, leading to improved efficiency and extended service life.
Implementation Method 1
pressure fluctuations can occur in this chamber, which can excite the burner insert to high-frequency oscillations
Implementation Method 2
The edge web of the burner insert according to the invention leads to an increase in the natural frequencies
Implementation Method 3
cooling air, which usually comes from the compressor, flows along the cold side from the combustor opening of the combustor liner to its outer edge
Implementation Method 4
the edge web is provided with openings for the passage of cooling fluid. In order to create the openings, the edge web has crenellations between which the openings are formed
Data Source
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AI summary
The invention relates to a burner insert (41) for a gas turbine combustion chamber (25), comprising a burner insert wall (42) having a cold side (43) and a hot side (44), and an edge (46) limiting the burner insert wall (42). The edge (46) has an edge bar (51) extending at least partially circumferentially and projecting beyond the cold side (43). A burner opening (45) for inserting a burner (27) is formed in the burner insert wall (42).