Abradable Turbine Wear Face With Guide Vanes for Leakage Flow Straightening

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Solution Overview

Problem

In turbomachines, the radial clearance between blades and the stator casing leads to significant leakage flow, reducing engine efficiency due to the differential expansions during operation, which cannot be completely eliminated, necessitating the use of abradable members to limit this leakage.

Innovation Solution

An abradable member with a cellular structure incorporating flow straighteners jutting from the wear face, manufactured via additive manufacturing, to straighten the leakage flow and align its gyration with the main flow, thereby improving engine efficiency by facilitating its re-introduction into the main flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If abradable members are used to limit leakage flow, then sealing performance is improved, but device complexity increases due to the cellular structure and flow straighteners

Engineering Contradiction:

Improvesealing performanceVSAvoidcellular structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The flow straighteners are integrated directly into the cellular structure of the abradable member, merging two functional elements (sealing and flow straightening) into a single unified component. This reduces the number of separate parts while maintaining both sealing performance and flow control functions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The abradable member employs a cellular (honeycomb) structure that provides both mechanical support and flow control functions. The porous cellular structure allows gas passage while maintaining structural integrity and enabling the integration of flow straighteners within the cells.

Inventive Principle:

Principle #31Porous materials

2Loss of energy

If radial clearance is reduced to minimize leakage flow, then energy efficiency is improved, but the risk of blade-to-stator contact increases

Engineering Contradiction:

Improveleakage flow rateVSAvoidblade-to-stator contact risk

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The abradable member material properties are designed to be softer than the blade material, allowing controlled material removal through rubbing. This parameter change in material hardness enables the clearance to be dynamically adjusted during operation without risking blade damage, as the abradable material yields preferentially.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The clearance between blades and stator is not fixed but dynamically adjusted through the abradable member wear mechanism. During operation, the rubbing fins gradually wear the abradable material, automatically reducing the clearance to an optimal value that minimizes leakage while preventing contact.

Inventive Principle:

Principle #15Dynamics

3Productivity

If flow straighteners are added to the abradable member, then leakage flow re-introduction efficiency is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveleakage flow re-introduction efficiencyVSAvoidmanufacturing complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The flow straighteners are manufactured as an integrated part of the abradable member's cellular structure, combining multiple functions into a single manufacturing process. This integration eliminates the need for separate assembly steps and reduces overall manufacturing complexity despite the enhanced functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The abradable member with integrated flow straighteners can be manufactured using additive manufacturing techniques, which excel at creating complex composite geometries. The process builds the cellular structure and flow straighteners in a single operation, managing complexity through advanced manufacturing rather than traditional assembly.

Inventive Principle:

Principle #40Composite materials

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 straightening of leakage flow reduces its gyration, minimizing pressure losses and enhancing turbine efficiency by effectively reintroducing it into the main stream, leading to improved engine performance.

Implementation Method 1

the leakage flow is straightened to bring its gyration to a value close to that of the main flow in order to facilitate its re-introduction into the main flow downstream of the abradable member

Methodology Applied

Scientific EffectFlow straightening:

Implementation Method 2

the invention is directed to an abradable member for a turbomachine turbine, comprising a cellular structure comprising walls defining wells which open through a wear face

Methodology Applied

Scientific EffectCellular structure support:

Implementation Method 3

the cellular structure is obtained by additive manufacturing

Methodology Applied

Scientific EffectAdditive manufacturing: 3D Printing

Implementation Method 4

the at least one flow straightener has a curved wall fastened to a well

Methodology Applied

Scientific EffectCurved surface flow redirection:

Data Source

PatentUS11994032B2Abradable member for a turbine of a turbomachine, comprising a wear face provided with guide vanes

Publication Date: 2024.05.28 SAFRAN AIRCRAFT ENGINES SAS

AI summary

An abradable member for a turbomachine turbine, including a cellular structure including walls defining wells which open through a wear face. The cellular structure includes at least one flow straightener jutting from the wear face.