Elastically Deformable Annular Support for Turbine Casing Distortion
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Solution Overview
Problem
Existing turbomachine designs face challenges in maintaining optimal radial clearances between blade wheels and ring sectors due to carcass distortions caused by non-uniform cooling air circulations, leading to efficiency deterioration and uncontrolled displacements, which previous solutions like stiffening the annular support or fixing it directly to the casing fail to adequately address.
Innovation Solution
An elastically deformable annular support with a V or U-shape section, comprising two coaxial annular walls that can absorb carcass distortions and maintain constant radial clearances, providing both radial flexibility and axial rigidity to resist combustion gas thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the annular support is stiffened by forming it in one piece with the support casing, then the axial rigidity is improved, but the radial flexibility to absorb carcass distortions deteriorates
Solution Approach 1:
The annular support is segmented into multiple independent ring sectors that can move radially relative to each other. This segmentation allows the support to maintain axial rigidity through its overall structure while providing radial flexibility through the ability of individual sectors to adjust position, thereby absorbing carcass distortions without compromising axial strength.
Solution Approach 2:
Different regions of the annular support have different mechanical properties. The support structure is designed with locally optimized characteristics where certain areas provide axial stiffness while other areas allow radial movement. This local differentiation enables the support to simultaneously achieve axial rigidity and radial flexibility to accommodate casing deformations.
2Strength
If the ring sectors are fixedly connected to the support casing, then the axial rigidity is improved, but the ability to optimize radial clearances as a function of speed deteriorates
Solution Approach 1:
The connection between ring sectors and support casing transitions from a fixed static connection to a dynamic adjustable connection. The radial positioning means enable the ring sectors to move radially relative to the support casing, allowing the radial clearances to be optimized as a function of turbomachine speed while maintaining adequate axial rigidity through the overall structural design.
3Strength
If the support is fixed directly to the turbine casing, then the axial rigidity is improved, but the displacements of ring sectors due to carcass distortions deteriorate
Solution Approach 1:
The annular support acts as an intermediary element between the turbine casing and the ring sectors. It provides a stable mounting platform for the ring sectors while being sufficiently compliant to absorb the carcass distortions of the turbine casing. This intermediary structure isolates the ring sectors from direct exposure to casing deformations, maintaining radial clearance stability while achieving axial rigidity.
4Strength
If the axial rigidity of the support is increased by using large axial fastening means, then the resistance to axial thrust is improved, but the device complexity and axial space occupation deteriorate
Solution Approach 1:
The axial fastening function and the radial adjustment function are merged into an integrated support structure. The annular support combines axial mounting features with radial positioning capabilities in a unified design, eliminating the need for separate large axial fastening means. This integration reduces device complexity and axial space occupation while maintaining adequate axial resistance to thrust forces.
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 solution ensures a constant radial clearance between the wheel and ring sectors, improving turbomachine efficiency by dampening carcass distortions and maintaining precise radial clearance adjustments across varying operating speeds.
Implementation Method 1
the annular support comprises means for attachment of the ring sectors and the fastening means to the turbine casing, connected by two coaxial annular walls connected to each other and extending one inside the other, this support having a V or U-shape in section and being elastically deformable in the radial direction to at least partially absorb the deformations of the turbine casing in operation
Data Source
AI summary
Ring sectors (20) are arranged about a turbine impeller (18) and are suspended from a turbine casing (22) by an annular support (50). The annular support supports the ring sectors and attaches to the turbine casing. The annular support deforms elastically in the radial direction to partly cushion the carcass distortions where the turbine casing is subjected in operation of the turbomachine turbine. An independent claim is included for the turbomachine turbine.