Brush Seal on Turbomachine Compressor Inner Shroud

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Solution Overview

Problem

The re-circulation phenomenon under the stator in turbomachine compressors degrades operability and aerodynamic performance, and existing solutions like rotor shroud lips are costly and ineffective.

Innovation Solution

An angular stator sector with a brush seal on the inner shroud to obstruct gas recirculation and extend the aerodynamic stream pattern, preventing descending steps and improving compressor performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If rotor shroud lips are installed to reduce gas recirculation, then recirculation flow is reduced, but manufacturing cost increases and effectiveness depends on prediction and manufacture quality

Engineering Contradiction:

Improvegas recirculationVSAvoidmanufacturing cost and complexity

Core Design Contradiction:

Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent replaces expensive, precision-manufactured rotor shroud lips with a brush seal that can be easily manufactured and installed. The brush seal uses inexpensive brush material that can be replaced if needed, eliminating the high manufacturing costs and quality control requirements associated with precision lips.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the approach from using rigid lips with specific geometric parameters to a flexible brush seal where the sealing parameter is the brush bristle density and length. This allows easier adjustment and manufacturing without requiring precise geometric predictions.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If descending steps are created between successive compressor parts, then manufacturing is simplified, but aerodynamic performance deteriorates

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidaerodynamic performance

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The brush seal acts as an intermediary element between successive compressor parts with different radii. It allows the maintaining of descending steps for manufacturing simplicity while mitigating their negative aerodynamic effects, serving as a mediator between the conflicting requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Significantly reduces gas recirculation and enhances aerodynamic performance by forming obstacles with brush seals, potentially replacing or supplementing existing lip solutions.

Implementation Method 1

the inner shroud comprises at least one brush seal forming an obstacle to the recirculation of the downstream gases upstream of the inner shroud

Methodology Applied

Scientific EffectBrush seal obstruction: Friction

Data Source

PatentUS10330117B2Angular stator sector for a turbomachine compressor comprising a brush seal

Publication Date: 2019.06.25 SAFRAN AIRCRAFT ENGINES SAS

AI summary

The main object of the invention is an angular stator sector (10) for a turbomachine compressor, comprising an outer shroud and an inner shroud (S) arranged coaxially one inside the other, and at least one vane (P) extending radially between the outer shroud and the inner shroud (S) and connected to the latter by its radial ends, characterized in that the inner shroud (S) comprises at least one brush seal (1, 2, 3) forming an obstacle to the recirculation of the downstream gases upstream of the inner shroud (S).