Segmented Composite Shroud Ring for Axial Compressor
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Solution Overview
Problem
The segmentation of the inner shroud in axial turbomachines can lead to degraded aerodynamic characteristics due to misalignment and precision issues at the junctions between segments, which is not present in a one-piece ferrule.
Innovation Solution
The inner shroud is designed as multiple arc-shaped segments with profiled ends that match the blade profiles, connected by an elastomer to ensure precise alignment and interlocking, with positive contact means providing a secure and flexible connection, allowing for differential expansions and maintaining aerodynamic integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inner shroud is segmented into multiple sections, then the ease of manufacture is improved and differential expansions are compensated, but the aerodynamic characteristics are degraded due to misalignment at junctions
Solution Approach 1:
The inner shroud is divided into multiple segments that can be manufactured separately and assembled together. This segmentation allows for easier manufacturing of complex composite structures and compensation of differential thermal expansions between different parts of the stator assembly.
Solution Approach 2:
An elastomer material is introduced as an intermediary substance at the junctions between segments. This elastomer compensates for misalignments and gaps that occur during assembly, ensuring that the aerodynamic flow is not significantly disturbed despite the segmented construction.
2Ease of operation
If the inner shroud is segmented into multiple sections, then the ease of assembly is improved, but the device complexity increases due to connection means
Solution Approach 1:
An elastomeric material is used to create a flexible connection between the rigid segments. This flexible element simplifies the assembly process by accommodating misalignments and providing a seal, while the segments themselves maintain their structural integrity and aerodynamic function.
3Manufacturing precision
If the junction area is reduced to minimize fluid flow disturbance, then the aerodynamic performance is improved, but the connection strength between segments is reduced
Solution Approach 1:
The junction between segments uses a composite construction where rigid segment ends provide structural strength and aerodynamic accuracy, while an elastomeric material provides sealing and flexibility. This composite approach allows for a small junction area that maintains both aerodynamic performance and connection strength.
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 minimizes the disturbance to fluid flow by reducing the size of the junction area, maintaining aerodynamic performance similar to a one-piece shroud while accommodating material differences and expansions.
Implementation Method 1
the connection at the junction between the blades and the segments being ensured by an elastomer
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The shroud (8) has arc shape segments (8a, 8b) with an exterior surface including openings (10). The openings receive an end of a vane (4) of a stator. An end of the segments has sections (11a, 11b), whose profile corresponds to profile of an end of the vane, when the segment is placed on the vane of the stator so that a junction between the segments corresponds to the section of the vane. A connection at level of another junction between the vane and the segments is provided by an application of elastomer, during assembling the segments on the vane. The segments are made of a composite material e.g. material comprising a resin associated to carbon fibers and/or glass fibers.