Gas Turbine Guide Blade Trailing Edge Stress Reduction
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Solution Overview
Problem
The transition area between the trailing edge and the cover plate in existing gas turbine guide vanes experiences high thermal and mechanical stresses due to thermal-mechanical mismatch, leading to reduced service life, especially under high operating temperatures.
Innovation Solution
A groove is introduced on the cover plate between the receiving groove and the trailing edge, reducing material thickness and thermal and mechanical stresses, and the trailing edge is set back to further decouple thermal loads, while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cover plate with large material volume is used to provide structural strength, then the mechanical strength is improved, but the thermal stresses increase significantly leading to reduced service life
Solution Approach 1:
The cover plate is designed with non-uniform thickness, featuring a reduced thickness section specifically at the transition area to the trailing edge. This local modification reduces thermal stress concentration in the critical region while maintaining adequate material volume elsewhere to preserve overall structural strength.
Solution Approach 2:
The cover plate is segmented into regions of different thicknesses, with a distinct reduced thickness section separating the main body from the trailing edge area. This segmentation allows differential thermal-mechanical behavior in different zones, protecting the critical transition area from excessive stresses.
2Stability of the object's composition
If the transition area between trailing edge and cover plate is designed with large material volume, then structural integrity is improved, but thermal and mechanical stresses increase leading to reduced service life
Solution Approach 1:
The cover plate features a localized reduced thickness section at the transition area, creating a specific zone with different mechanical and thermal properties. This local modification reduces stress concentration while maintaining overall structural integrity through adequate material volume in other regions.
3Duration of action of stationary object
If means are provided on the cover plate to reduce thermal and mechanical stresses, then service life is improved, but device complexity increases
Solution Approach 1:
The solution implements a simple geometric modification - a reduced thickness section - rather than adding complex components or systems. This single design feature directly addresses the thermal-stress problem while maintaining manufacturing simplicity and avoiding increased device complexity.
Data Source
Figure 1
Figure 2~3
AI summary
A guide blade (20) for a gas turbine comprises a blade leaf (11), which extends in the blade longitudinal direction, and is delimited by a front edge (14) and a rear edge (15), and a cover plate (12), the inner side (19) thereof being subjected to the hot gas flowing through the gas turbine, and on which a hooked fastener (17) for fastening the guide blade (20) on a housing of the gas turbine is provided protruding outward in the area of the rear edge, said fastener (17) having a receiving groove (22) for fixing a heat accumulation segment (24), which adjoins the cover plate (12) of the guide blade (20) in the flow direction of the hot gas, on the side thereof facing toward the rear edge (15) above the rear edge (15). In such a guide blade, the service life is lengthened in that means (23) are provided on the cover plate (12) of the guide blade (20) between the receiving groove (22) and the rear edge (15) for reducing the thermal and mechanical strains in the area of the transition (21) between rear edge (15) and cover plate (12).