Turbomachine Stator Ring with Variable Chords for Aerothermal Balance

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Solution Overview

Problem

Existing stator wheels in turbomachines face challenges in optimizing both aerodynamic and thermal performance while maintaining mechanical robustness, as conventional designs compromise between these functions, leading to suboptimal overall performance.

Innovation Solution

A stator wheel design with varying blade chords, incorporating both aerodynamic and thermal profiles, allows for specialized blade functions without disrupting the overall airflow, using intermediate blades for smooth transitions and minimizing local disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cross-section of stator blades is increased to improve mechanical stiffness and reduce stresses, then structural strength is improved, but aerodynamic performance deteriorates due to deviation from optimal blade profile

Engineering Contradiction:
Improvemechanical stiffnessVSAvoidaerodynamic performance
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating blade characteristics based on position. Blades are categorized into first blades (at specific positions) with enhanced cross-section for structural roles, and second blades with optimized aerodynamic profiles. This localized differentiation allows each blade to perform its specific function optimally without compromising overall system performance.

Inventive Principle:
Principle #3Local quality

2Temperature

If the surface area of stator blades is increased to maximize heat exchange between primary and secondary air flows, then thermal performance is improved, but aerodynamic performance deteriorates due to profile deviation

Engineering Contradiction:
Improveheat exchangeVSAvoidaerodynamic performance
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The patent implements local quality by assigning different blade profiles to different positions. First blades have enlarged cross-sections that increase thermal exchange surface area, while second blades maintain aerodynamically optimized profiles. This spatial differentiation enables simultaneous optimization of thermal and aerodynamic functions in different locations within the stator wheel.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If all stator blades are designed with identical compromise profiles to fulfill multiple functions, then manufacturing simplicity is maintained, but overall turbomachine performance is reduced

Engineering Contradiction:
Improveblade uniformityVSAvoidturbomachine performance
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent resolves this contradiction by applying local quality - differentiating blade designs based on positional requirements rather than using uniform compromise profiles. First blades at specific positions have structural/thermal optimizations, while second blades have aerodynamic optimizations. This targeted differentiation improves overall turbomachine performance while maintaining manufacturing feasibility through clear categorization.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies segmentation by dividing the stator blade population into distinct groups (first blades and second blades) with different functional characteristics. This segmentation allows each group to be optimized for its specific role - structural support or aerodynamic efficiency - rather than forcing all blades into a single compromise design.

Inventive Principle:
Principle #1Segmentation

4Strength

If the chord length of stator blades is increased to improve structural role and heat exchange, then mechanical and thermal functions are improved, but aerodynamic performance is penalized

Engineering Contradiction:
Improvestructural roleVSAvoidaerodynamic performance
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent applies local quality by positioning blades with increased chord length (first blades) at specific locations where structural support and heat exchange are prioritized, while maintaining standard chord length for second blades where aerodynamic performance is critical. This spatial differentiation allows chord length optimization for specific functional requirements without penalizing overall aerodynamic performance.

Inventive Principle:
Principle #3Local quality

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 design ensures optimal airflow straightening and thermal exchange while maintaining mechanical integrity, thus enhancing turbomachine efficiency without penalizing performance.

Implementation Method 1

The stator blades 3 have a precise and predefined geometry making it possible to best ensure the aforementioned functions. The stator blades 3 are dimensioned so as to have a predefined section and orientation to optimize the deflection of the second air flow F2.

Methodology Applied
Scientific EffectAerodynamic deflection: Aerofoil

Implementation Method 2

the latter can for example be used to improve the recovery and transmission of forces in the turbomachine or the heat exchange between the hot primary air flow F1 circulating inside the intermediate casing 12 and a cold secondary air flow F2 circulating outside said intermediate casing 12.

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3927945B1Turbomachine stator ring comprising stator vanes with different chord lenght
Publication Date: 2025.07.30 SAFRAN AIRCRAFT ENGINES SAS
  • EP3927945B1 patent drawingFigure 1~2
  • EP3927945B1 patent drawingFigure 3
  • EP3927945B1 patent drawingFigure 4

AI summary

Disclosed is a stator wheel of a turbomachine intended to be mounted in an aircraft, the turbomachine extending along an axis X, the turbomachine comprising a primary flow path for a first flow of air and a secondary flow path for a second flow of air in which the stator wheel is intended to be mounted according to the axis X, the stator wheel (4) comprising a plurality of blades (40) extending radially according to the axis, each blade (40) comprising a leading edge and a trailing edge that together define a chord (C1, C2, C31, C32) in a plane of revolution (PR) defined relative to the axis, at least two blades (40) having different chords (C1, C2, C31, C32) at a same radial distance, the chord (C1, C2, C31, C32) difference between two adjacent blades (40) being less than or equal to 25%.