Compressor Vane Tip Clearance Reduction via Elastic Shroud

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Solution Overview

Problem

Cantilever type compressors face challenges in minimizing vane tip clearance due to thermal expansion, leading to leakage flows and increased manufacturing costs, while shrouded types eliminate leakage but are more expensive and time-consuming to manufacture.

Innovation Solution

Incorporating an elastic member between the shroud segment and the diffuser to absorb collision impacts from vane expansion, minimizing vane tip clearance and eliminating leakage by compressing during operation, and using a sealing member to prevent axial gaps and leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cantilever type compressor vanes are used, then manufacturing cost and assembly time are reduced, but vane tip clearance increases causing leakage flows

Engineering Contradiction:
Improvemanufacturing cost and assembly timeVSAvoidleakage flow
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The shroud segment is designed to be movable rather than fixed, allowing it to dynamically adjust its position in response to thermal expansion of the vanes. The elastic member enables the shroud segment to move radially inward when vanes expand, maintaining contact and minimizing clearance without requiring complex active control systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system utilizes thermal expansion parameters of the vane material to design the movable shroud mechanism. As temperature increases during operation, the vane expands radially, and the elastic member compensates for this parameter change by allowing the shroud segment to move accordingly, maintaining optimal clearance throughout the thermal cycle.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If shrouded type compressor vanes are used, then vane tip clearance is eliminated and leakage flow is prevented, but manufacturing cost and assembly time increase

Engineering Contradiction:
Improveleakage flowVSAvoidmanufacturing cost and assembly time
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

Instead of using a complete shroud that encloses all vanes (shrouded type), the invention applies segmentation by providing a shroud segment that only covers the critical vane tip area where leakage occurs. This partial coverage achieves the leakage prevention function while significantly reducing manufacturing complexity and assembly time compared to a full shroud design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The elastic member serves as an intermediary element between the fixed diffuser and the movable shroud segment. It transmits and absorbs the thermal expansion forces, enabling the shroud segment to maintain contact with the vane tip without requiring direct mechanical connection or complex adjustment mechanisms, thus simplifying the overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-generated harmful factors

If vane tip clearance is minimized, then leakage flow is reduced and aerodynamic performance is enhanced, but collision impact from thermal expansion occurs

Engineering Contradiction:
Improveleakage flowVSAvoidcollision impact
Core Design Contradiction:
Object-generated harmful factorsVSForce

Solution Approach 1:

The elastic member is installed in advance between the shroud segment and diffuser to provide cushioning against thermal expansion forces. Before collision can occur, the elastic member compresses and absorbs the impact energy, preventing damage to the rigid components while maintaining the minimized clearance configuration for optimal aerodynamic performance.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 allows for easy manufacturing and assembly of cantilever type compressors while minimizing vane tip clearance, reducing leakage flows, and enhancing aerodynamic performance by absorbing collision forces and preventing axial gaps.

Implementation Method 1

an elastic member installed between the shroud segment and the diffuser, and absorbing a collision impact and being compressed when the vane collides with the shroud segment due to expansion of the vane

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4223988B1Compressor with reduced vane tip clearance
Publication Date: 2024.10.30 DOOSAN ENERBILITY CO LTD
  • EP4223988B1 patent drawingFigure 1~2
  • EP4223988B1 patent drawingFigure 3~4
  • EP4223988B1 patent drawingFigure 5

AI summary

Disclosed are a compressor, which is a cantilever type that is easy to manufacture and assemble, and is capable of minimizing the vane tip clearance as the elastic member absorbs the impact and is compressed when the vane collides with the shroud segment due to expansion of the vane, and a gas turbine including the same.