Gas Turbine Combustor Corner Seal Design
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Solution Overview
Problem
Current gas turbine combustor designs experience leakage of combustion air due to thermal deformation and vibration, leading to reduced energy efficiency and increased NOx emissions, despite existing sealing structures that struggle to maintain effective sealing at the connection portion between the transition duct and the gas turbine nozzle, particularly at the corners where sealing members intersect.
Innovation Solution
The implementation of a corner seal independent of the floating and side seals, placed in the gap between adjacent aft frame corners, enhances sealing performance by preventing air leakage from the intersection points, utilizing a configuration that includes T-shaped and U-shaped sealing portions with specific engagement and fixing mechanisms to maintain sealing efficacy amidst thermal expansion and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing members (floating seal and side seal) are placed at the intersection of aft frame corners to prevent air leakage, then sealing performance is improved, but the sealing members interfere with each other due to thermal deformation and vibration
Solution Approach 1:
The sealing function is divided into multiple independent sealing members: floating seals placed on inner and outer peripheral portions of the aft frame, side seals placed on side portions of the aft frame, and corner seals placed at corner portions. Each sealing member independently seals its specific gap portion, avoiding interference while comprehensively sealing all leakage paths.
Solution Approach 2:
Different sealing members are placed at different locations (inner peripheral portion, outer peripheral portion, side portions, and corner portions) with each having specific engagement structures tailored to its location. The floating seal engages with the combustion liner, the side seal engages with adjacent aft frames, and the corner seal engages with corner portions, providing localized sealing solutions for each specific gap.
2Adaptability or versatility
If gap portions are provided between sealing members to accommodate thermal deformation, then adaptability to thermal expansion is improved, but air leakage paths increase
Solution Approach 1:
The sealing system is segmented into multiple sealing members positioned at different locations (floating seals at inner and outer peripheries, side seals at side portions, corner seals at corner portions). This segmentation allows each sealing member to independently accommodate thermal deformation in its specific location while collectively blocking all air leakage paths through coordinated sealing action.
Solution Approach 2:
The sealing approach transitions from a single-dimension linear seal to a multi-dimensional comprehensive sealing system covering inner periphery, outer periphery, side portions, and corner portions. This multi-dimensional arrangement ensures that thermal deformation in any direction is accommodated while maintaining complete sealing coverage.
Data Source
AI summary
A gas turbine combustor includes multiple aft frames each having a floating seal that seals a gap between an aft frame and a gas turbine in inner and outer peripheries of the aft frame, and a side seal that seals a gap between the aft frames adjacent to each other in a circumferential direction, and a corner seal that is placed in a gap portion provided between corner portions of the aft frames adjacent to each other in the circumferential direction, seals air leaking from at least the gap portion into the gas turbine side, and is independent of the floating seal and the side seal.