Welded Combustor Shell Film Cooling
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Solution Overview
Problem
Annular gas turbine combustors face issues with thermal distortion and stress due to flange connections, leading to reduced service life and uncontrolled leaks, which affect performance and emissions.
Innovation Solution
The use of rotationally symmetrical sheet metal shells with a welded parting line seam and film cooling, along with a heat protection layer, to minimize distortion and ensure reliable sealing, combined with parting line elements for improved cooling and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If flange connections are used to join combustion chamber shells, then the shells can be assembled and disassembled easily, but thermal distortion and stress occur due to different thermal expansion between flange and free shell areas
Solution Approach 1:
The combustion chamber shell is divided into multiple segments that are joined by welding at parting lines. This segmentation allows each segment to be manufactured separately and then permanently joined, eliminating the need for flange connections while maintaining assembly capability during manufacturing.
Solution Approach 2:
The patent merges the joining function into the shell structure itself by integrating parting lines directly into the shell geometry. The welded joints are made as part of the shell fabrication process rather than as separate connection components, creating a unified thermal and structural field.
2Adaptability or versatility
If flange connections are used to join combustion chamber shells, then modular assembly is enabled, but sealing reliability deteriorates due to difficulty in reliably sealing flange connections in hot gas area
Solution Approach 1:
The shell segments are prepared with precise parting line geometries and edge profiles before assembly. The welding surfaces are pre-configured to ensure proper fit-up and sealing, eliminating the need for separate sealing components that would be required with flange connections.
Solution Approach 2:
The parting line geometry is precisely replicated across all shell segments to ensure consistent mating surfaces. This copying of the parting line profile across multiple segments enables reliable welded joints with proper sealing, replacing the sealing function that would otherwise require complex flange designs.
3Ease of repair
If welding repairs are performed on combustion chamber shells, then damaged sections can be replaced, but material properties are reduced in the weld seam area creating weak points
Solution Approach 1:
The shell is designed with parting lines positioned to facilitate repair welding. The geometry and thickness parameters at the parting lines are optimized to allow for high-quality weld repairs that maintain material properties, and the design anticipates future repair needs by providing accessible welding surfaces.
4Reliability
If welded parting line seams are used to join shells, then reliable sealing is achieved, but thermal distortion may occur during welding process
Solution Approach 1:
The shell design incorporates local geometric features at the parting lines, such as specific edge profiles and thickness variations, that are optimized for welding. These local quality changes at the joint areas facilitate low-distortion welding while maintaining overall shell integrity and sealing reliability.
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
This solution reduces material consumption, prevents thermal distortion, and ensures reliable sealing, thereby enhancing the service life and reducing emissions by minimizing uncontrolled leaks and thermal stresses.
Implementation Method 1
In order to ensure the service life of the at least one parting line weld seam, film cooling of the parting line weld seam is proposed
Implementation Method 2
the application of the protective layers (105, 106) is carried out in a two-stage process
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a gas turbine having ring-shaped inner and/or outer shells (8, 7) of an annular combustion chamber (3), the closure of the inner and/or outer shells (8, 7), and a method for repairing said closure. In order to create an annular combustion chamber (3) that can be heated without thermal distortion, expands without distortion, and can be reliably closed, opened for repairs, and permanently closed again, and that can be reconditioned, the inner and/or outer shells (8, 7) of an annular combustion chamber (3) are made of a rotationally symmetrical metal sheet. The shells are cut in a parting plane (16) for assembly, and the lower half of the inner and outer shell (8, 7) are installed into the lower half of the housing of a gas turbine. After the rotor is installed, the two upper shell halves can also be installed, and joined to the lower halves by welding. In order to improve the service life of the parting plane weld seam (21), film cooling of the weld joint is proposed, guided by an indentation. Said indentation can, for example, be implemented by welded parting plane elements (15) that are also suitable for retrofitting.