Labyrinth Seal Support Ring for Compressor Erosion Mitigation

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Solution Overview

Problem

Erosion damage to the bearing support housing in aircraft cabin air compressors occurs due to foreign object particles bypassing the labyrinth seal and impacting the housing, leading to reduced service life.

Innovation Solution

A centrifugal compressor assembly with a labyrinth seal and a seal support ring featuring a deflector ramp and tortuous pathways to divert airflow radially inward and diffuse tangential components, reducing the impact on the bearing support housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a labyrinth seal is used to seal the interface between the impeller and bearing support housing, then sealing effectiveness is improved, but erosion damage to the bearing support housing occurs due to particles bypassing the seal

Engineering Contradiction:
Improvesealing effectivenessVSAvoiderosion damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A seal support ring is introduced as an intermediary component between the labyrinth seal and the bearing support housing. This ring intercepts particles that bypass the labyrinth seal and redirects them away from the housing, preventing erosion while maintaining the sealing function of the labyrinth seal.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The seal support ring utilizes the kinetic energy and flow direction of particles bypassing the seal (harmful factor) and redirects this flow through deflector ramps and tortuous pathways to protect the housing (beneficial effect), converting the harmful particle transport into a protective function.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Duration of action of stationary object

If the bearing support housing is made more erosion-resistant, then service life is extended, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveservice lifeVSAvoidhousing structure complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The erosion protection function is extracted from the bearing support housing itself and implemented as a separate seal support ring component. This allows the housing to remain simple while the dedicated ring provides erosion resistance through its deflector ramps and tortuous pathways.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sealing and protection system is segmented into distinct components: the labyrinth seal for sealing, the seal support ring for particle interception, and the deflector ramps/tortuous pathways for flow redirection. This segmentation allows each component to be optimized independently and simplifies the overall housing design.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If a seal support ring with deflector ramps and tortuous pathways is added, then erosion protection is improved, but device complexity increases

Engineering Contradiction:
Improveerosion protectionVSAvoidseal assembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The seal support ring serves multiple functions simultaneously: it provides structural support for the labyrinth seal, intercepts particles bypassing the seal, redirects airflow away from the housing, and creates tortuous pathways that further protect the housing. This multi-functionality reduces the need for additional separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The deflector ramps and tortuous pathways are integrated directly into the seal support ring structure, combining the support function with the erosion protection function in a single component rather than requiring separate protective structures.

Inventive Principle:
Principle #5Merging (Combining)

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 reduces erosion of the bearing support housing, extending the service life of the compressor by diverting and diffusing airflow, thereby mitigating damage.

Implementation Method 1

The deflector ramp is configured to turn an airflow leaking through the seal interface radially inwardly toward the central axis

Methodology Applied
Scientific EffectFluid deflection:

Implementation Method 2

A plurality of tortuous pathways are formed in a downstream surface of the seal support ring and are configured to diffuse a tangential component of the airflow

Methodology Applied
Scientific EffectFlow diffusion: Diffusion

Data Source

PatentEP4043736B1Erosion mitigating labyrinth seal mating ring
Publication Date: 2024.09.11 HAMILTON SUNDSTRAND CORP
  • EP4043736B1 patent drawingFigure 1
  • EP4043736B1 patent drawingFigure 2
  • EP4043736B1 patent drawingFigure 3

AI summary

A compressor assembly includes an impeller (14) rotatable about a central axis and a seal assembly. The seal assembly includes a labyrinth seal (32) defining a seal interface with a sealing element of the impeller (14) and a seal support ring into which the labyrinth seal (32) is installed. The seal support includes a deflector ramp (54) fluidly downstream of the seal interface. The deflector ramp (54) is configured to turn an airflow leaking through the seal interface radially inwardly toward the central axis. A plurality of tortuous pathways are formed in a downstream surface of the seal support ring and are configured to diffuse a tangential component of the airflow.