Stator Vane Shroud Step Area Limits Axial Shift

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Solution Overview

Problem

In turbomachines, circumferentially adjacent stator vanes experience high loads that can lead to undesirable axial shifting, complicating the design with additional features to prevent such movement.

Innovation Solution

A stator vane assembly with a cantilevered design and a shroud featuring a step area in its circumferential edge, which mimics the profile of adjacent vanes, limits axial movement by directing axial loads through specific surfaces and preventing load transfer through the step area, thus reducing the likelihood of shifting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If additional features are added to the turbomachine casing to limit axial movement of stator vanes, then axial shifting is prevented, but device complexity increases

Engineering Contradiction:
Improveaxial alignment stabilityVSAvoidcasing feature complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention merges the function of limiting axial movement into the shroud component itself by providing a circumferential edge with a step area that contacts adjacent vanes. This combines the shroud's structural support function with the additional function of preventing axial racking, eliminating the need for separate casing features and reducing overall device complexity while maintaining stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shroud structure serves itself by using its own circumferential edge geometry (the step area) to prevent axial shifting of adjacent vanes. The design makes the shroud self-sufficient for both supporting the vane and preventing racking movements, without requiring external features from the casing.

Inventive Principle:
Principle #25Self-service

2Reliability

If the shroud circumferential edge includes a step area, then axial load transfer is prevented and shifting is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveshifting preventionVSAvoidshroud manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the geometric parameters of the shroud circumferential edge by introducing a step area with specific axial and radial dimensions. This parameter change creates distinct contact surfaces that prevent axial load transfer and reduce shifting, while the step area can be manufactured using standard machining or forming processes.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the first circumferential edge mimics the profile of the second circumferential edge, then adjacent vanes interface properly, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecircumferential alignmentVSAvoidedge profile precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The invention uses asymmetric step areas on each shroud circumferential edge, where the step area geometry is tailored to the specific interface requirements with adjacent vanes. Rather than requiring all edges to be identical, each edge is designed asymmetrically to match its specific neighboring vanes, improving compatibility while managing precision requirements through deliberate asymmetric design.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP2791474B1Stator vane assembly for turbomachine
Publication Date: 2019.04.03 UNITED TECH CORP
  • EP2791474B1 patent drawingFigure 1
  • EP2791474B1 patent drawingFigure 2~3
  • EP2791474B1 patent drawingFigure 4~5

AI summary

A stator vane assembly of a turbomachine according to an exemplary embodiment of the present disclosure includes, among other possible things, a shroud having a leading edge, a trailing edge, and at least one circumferential edge. The leading edge is circumferentially offset relative to the trailing edge when installed within the turbomachine. In a further embodiment of the foregoing stator vane assembly embodiment, the circumferential edge includes a portion that is aligned with an axis of the turbomachine. In a further embodiment of either of the foregoing stator vane embodiments, a vane extends radially from the shroud. In a further embodiment of any of the foregoing stator vane embodiments, the vane is a cantilevered vane.