Segmented Shroud Radial Displacement for Rotor Misalignment
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Solution Overview
Problem
Existing sealing devices for axial turbomachines fail to compensate for misalignment between the rotor and stator, leading to irreversible clearance variations and efficiency losses, as well as potential engine damage from particle release.
Innovation Solution
A segmented shroud with elastic means, such as elastomeric elements, allows radial movement to accommodate misalignment, ensuring the shroud can conform to changes in alignment and maintain a centered circular shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed shroud is used, then manufacturing precision is improved, but the device cannot compensate for rotor-stator misalignment
Solution Approach 1:
The shroud is divided into multiple independent segments that can move radially relative to the casing wall. Each segment is retained by elastic means allowing independent radial displacement, enabling the shroud to adapt to misalignment while maintaining overall structural integrity and manufacturing precision.
Solution Approach 2:
The shroud transitions from a fixed rigid structure to a dynamic structure where segments can radially displace elastically. The elastic retention means allow the segments to move dynamically in response to misalignment forces while returning to their original position when misalignment is removed.
2Adaptability or versatility
If a segmented shroud with radial movement capability is used, then misalignment compensation is improved, but manufacturing complexity increases
Solution Approach 1:
The shroud is segmented into multiple independent elements that can move radially. Each segment is retained by elastic means (such as elastomeric elements) that provide both retention and radial movement capability. This segmentation allows misalignment compensation while keeping individual segment manufacturing relatively simple.
Solution Approach 2:
The elastic means (e.g., elastomeric elements) provide a simple mechanism for radial movement through material elasticity rather than complex mechanical joints. The elastomeric material naturally provides both the retention force and the radial displacement capability, reducing structural complexity.
3Strength
If the shroud is made rigid for structural strength, then strength is improved, but the shroud cannot radially displace to compensate misalignment
Solution Approach 1:
The shroud is divided into segments that maintain structural strength through their rigid construction while allowing radial displacement at the retention points. The elastic means (elastomeric elements) provide the displacement mechanism without compromising the overall structural integrity of the shroud segments.
Solution Approach 2:
The elastomeric elements act as flexible retention means that allow radial movement while the shroud segments themselves remain rigid for structural strength. The combination of rigid segments and flexible retention creates a structure that is both strong and adaptable.
4Manufacturing precision
If abradable material is used for the shroud surface, then blade clearance control is improved, but particle release causes engine damage
Solution Approach 1:
The shroud segments can dynamically adjust their radial position through elastic displacement, maintaining optimal blade clearance without relying solely on abradable material erosion. This dynamic adjustment reduces the need for excessive abradable material, thereby reducing particle release while maintaining clearance control.
Solution Approach 2:
The elastic means provide a cushioning mechanism that allows controlled radial displacement before contact occurs, reducing the impact forces that would otherwise require thick abradable material layers. This pre-cushioning effect minimizes the amount of abradable material needed and consequently reduces particle generation.
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 effectively compensates for misalignment, maintaining efficient operation and preventing engine damage by allowing the shroud to radially displace and return to a centered position, utilizing elastomeric materials for damping and flexibility.
Implementation Method 1
elastic means, such as elastomeric elements, allows radial movement to accommodate misalignment
Implementation Method 2
utilizing elastomeric materials for damping and flexibility
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The housing (12) has a segmented shell (22) that is structured and operable to enclose a row of blades (24) and supported by a structural wall. Elastically deformable units (30) are positioned between the wall and segments of the shell so as to radially displace the segments in the event of contact with tips of the blades of a rotor and in the event of misalignment of a rotation axis of the rotor relative to an axis of the housing. The deformable units comprise elements made of elastically deformable materials e.g. elastomeric materials. An independent claim is also included for an axial turbomachine compressor.