Gas Turbine Combustor Deflector Panel Scallop Design
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Solution Overview
Problem
Gas turbine engine combustors face issues with deflector coating loss and cracking due to operating conditions, leading to reduced service life and high maintenance costs, despite attempts to mitigate these issues with cooling features that increase component costs.
Innovation Solution
A deflector panel design with panel scallops that define about 50% of the deflector opening, a wider panel neck, and studs located at the circumferential centerline to reduce stress and susceptibility to cracking, allowing for deflection and improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling holes and flow guides or cooling pins are added to the deflector, then resistance to erosion and cracking is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The deflector is segmented into multiple panels arranged in a circumferential array, with each panel being a separate, simpler component. This segmentation allows the complex cooling and erosion resistance features to be distributed across multiple simple panels rather than concentrated in one complex piece, reducing individual panel complexity while maintaining overall reliability.
Solution Approach 2:
The deflector panels incorporate localized features such as specific panel neck geometries and stud placements at critical stress points rather than uniform features across the entire deflector. This local quality approach provides enhanced erosion and cracking resistance at vulnerable locations without adding complexity to the entire structure.
2Ease of manufacture
If the deflector opening is positioned in the center of the deflector, then fuel injection is simplified, but circumferentially narrow portions develop coating loss and cracking
Solution Approach 1:
The central deflector opening is segmented into multiple smaller openings distributed across circumferentially adjacent panels. Each panel contains a portion of the total opening area, and the combined effect of all panels provides the required fuel injection area while eliminating the circumferentially narrow portions that lead to coating loss and cracking.
Solution Approach 2:
The solution transitions from a single-plane central opening to a distributed three-dimensional arrangement of multiple openings across multiple panels. This dimensional change allows the fuel injection function to be achieved while distributing stress and avoiding narrow circumferential sections.
3Strength
If mounting studs are placed at corners of the deflector, then structural support is provided, but stress concentration occurs at narrow portions between the deflector opening and circumferential edges
Solution Approach 1:
The mounting stud arrangement transitions from symmetric corner placement to an asymmetric distribution along the circumferential centerline of each panel. This asymmetric placement optimizes stress distribution by positioning studs away from the narrow circumferential portions, reducing stress concentration while maintaining structural support.
Solution Approach 2:
Mounting studs are strategically placed at specific locations on each panel rather than at all corners, with positioning optimized for each panel's local stress conditions. This local quality approach provides structural support where needed while avoiding stress concentration at vulnerable narrow portions.
Data Source
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Figure 3~4
AI summary
A deflector panel (76) for a combustor (52) of a gas turbine engine (20) includes an outer radial edge (80), an inner radial edge (78), and two circumferential edges (82a, 82b) extending between the outer radial edge (80) and the inner radial edge (78). Each circumferential edge (82a, 82b) includes a panel scallop (84) at least partially defining a deflector opening (72) receptive of a fuel nozzle (74) of the combustor (52). A combustor (52) of a gas turbine engine (20) includes a combustor shell (60) at least partially defining a combustion zone (62) therein, and a deflector assembly (64) operably connected to the combustor shell (60). The deflector assembly (64) includes a plurality of circumferentially abutted deflector panels (76). Each deflector panel (76) includes an outer radial edge (80), an inner radial edge (78), and two circumferential edges (82a, 82b) extending between the outer radial edge (80) and the inner radial edge (78). Each circumferential edge (82a, 82b) includes a panel scallop (84) at least partially defining a deflector opening (72). A fuel nozzle (74) extends through the deflector opening (72).