Turbine Combustor Side Seal Design for Thermal Expansion Leakage
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Solution Overview
Problem
The complex shapes and thermal cycling between the combustor outlets and the turbine inlet annulus in land-based turbine engines lead to non-uniform and unpredictable thermal expansions, causing small apertures to develop at the corners, which result in leakage of hot combustion gases and efficiency losses due to the existing seal configurations.
Innovation Solution
A method involving the arrangement of inner and outer circumferential seals between the annulus walls and combustor outlets, along with a side seal that extends across the entire height of the outer or inner circumferential seal, to effectively seal the space between adjacent combustor outlets, preventing gas leakage by conforming to the shape of the rear faces of the seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circumferential seals and side seals are provided between combustors and inlet annulus, then gas leakage is prevented, but aperture formation occurs due to non-uniform thermal expansion under thermal cycling
Solution Approach 1:
The sealing system is divided into multiple independent seal segments: inner circumferential seals, outer circumferential seals, and side seals positioned at different locations. This segmentation allows each seal to independently accommodate thermal expansion in its specific zone, preventing aperture formation while maintaining comprehensive sealing coverage.
Solution Approach 2:
The side seals act as intermediary elements that bridge the gap between adjacent combustors and accommodate differential thermal expansion. These side seals are strategically positioned to fill apertures that develop at the interfaces between combustors and the inlet annulus, serving as a mediator that maintains seal integrity under thermal cycling.
2Area of stationary object
If combustors are arranged around the inlet annulus with seals, then complete sealing coverage is achieved, but complex shapes cause non-uniform thermal expansion and aperture development
Solution Approach 1:
Different seal designs and materials are applied to different locations based on local thermal and mechanical conditions. The side seals at corner locations have different geometric configurations compared to seals in straight sections, allowing each seal to optimize its performance for its specific location's thermal expansion pattern.
Solution Approach 2:
The seal system is designed to be dynamically adaptive to thermal expansion. The seals are positioned and dimensioned to allow for movement and deformation under thermal cycling, with side seals specifically designed to accommodate the dynamic changes in aperture size and shape that occur during temperature transitions.
3Reliability
If side seal extends across entire height of circumferential seal, then aperture formation is prevented, but device complexity increases
Solution Approach 1:
The side seal is designed to extend across and integrate with both the inner and outer circumferential seals, merging multiple sealing functions into a single continuous sealing barrier. This unified seal structure prevents aperture formation at the interfaces while reducing the number of separate seal components needed, thereby simplifying the overall assembly.
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
The solution provides a robust seal that prevents aperture development at the corners, reducing gas leakage and enhancing the overall efficiency of the turbine engine by ensuring a tighter seal between the combustor outlets and the turbine inlet annulus.
Implementation Method 1
The thermal cycling between room temperature and the high temperatures that exist during normal operations can cause significant thermal expansions to occur. And because of the complex shapes of the individual elements which come together at the inlet annulus, the expansions can be non-uniform and unpredictable.
Data Source
AI summary
A side seal for sealing the side edges of adjacent combustors of a turbine engine include extended ends. The extended ends of the side seal abut and seal against inner and outer circumferential seals to prevent leakage of combustion gases.