Gas Turbine Combustion Duct Spring Seal Stiffness
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Solution Overview
Problem
The existing combustion duct assembly for gas turbines suffers from reduced joint stiffness between the liner and transition piece due to the long slit in the spring seal, which complicates manufacturing and limits the cooling effect.
Innovation Solution
A combustion duct assembly design where only the end portion of the spring seal is fixed to the liner, with through holes formed on the upstream side from the point of contact, and vent holes in the liner to enhance cooling, maintaining elastic support and improving cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a long slit is formed in the spring seal to allow compressed air flow, then cooling effect is improved, but joint stiffness between liner and transition piece deteriorates
Solution Approach 1:
The long slit in the spring seal is divided into multiple segments by forming protrusions that extend in the axial direction. This segmentation allows compressed air to pass through while maintaining the structural integrity and joint stiffness of the spring seal, resolving the contradiction between cooling effect and joint stiffness.
Solution Approach 2:
Protrusions are strategically positioned at specific locations on the spring seal to create localized structures that guide compressed air flow. This local modification enables effective cooling while preserving the overall structural strength and joint stiffness of the spring seal assembly.
2Temperature
If a hollow double wall structure is formed in the liner to enable compressed air flow, then cooling effect is improved, but manufacturing complexity increases
Solution Approach 1:
The cooling function is extracted from the liner wall structure itself and relocated to the spring seal assembly. By forming protrusions on the spring seal that guide compressed air flow, the need for a complex hollow double wall structure in the liner is eliminated, simplifying manufacturing while maintaining cooling effectiveness.
Solution Approach 2:
The spring seal with protrusions acts as an intermediary structure that mediates between the compressed air supply and the liner cooling requirement. This intermediary approach enables cooling without requiring complex modifications to the liner structure, thereby simplifying the manufacturing process.
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 design maintains joint stiffness and enhances cooling by forming through holes only on the upstream side of the spring seal and vent holes in the liner, achieving a film cooling effect that prevents heat transfer effectively.
Implementation Method 1
the transition piece has a double tube structure including: an inner wall which elastically gets in contact with the convex part of the spring seal attached to the downstream side of the liner
Implementation Method 2
a plurality of through holes are formed to a half of the upstream side from the point where the spring seal comes into contact with the inner wall, and wherein the liner has a plurality of vent holes formed in an inner area surrounded by the spring seal
Implementation Method 3
achieving a film cooling effect that prevents heat transfer effectively
Data Source
AI summary
A combustion duct assembly for a gas turbine includes a liner, an annular spring seal and a transition piece. The annular spring seal is outwardly convex and coupled to an outer face of the downstream side of the liner. The transition piece has includes an inner wall and an outer wall that surrounds the inner wall. The convex part of annular spring seal is operable to elastically engage the inner wall of the transition piece. An end portion of the downstream side of the annular spring seal is fixed to the line. The annular spring seal includes a plurality of through holes formed in an upstream side of a point where the annular spring seal comes into contact with the inner wall. The liner includes a plurality of vent holes formed in an inner area surrounded by the spring seal.