Composite Casing with Metal Flange for Axial Compressor

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Solution Overview

Problem

Current composite annular casings for axial turbomachines face challenges in reducing production costs and mechanical stresses, often resulting in heavier structures due to the use of metallic elements and complex attachment mechanisms.

Innovation Solution

The design incorporates an annular flange with an 'L' shaped profile, made of a different material than the composite annular wall, featuring radial and axial portions that distribute forces and reduce stress concentrations, along with a resin injection process for manufacturing, allowing for modular assembly and simplified repair.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal radial flanges are used to reinforce the composite annular wall, then mechanical strength is improved, but the overall weight increases

Engineering Contradiction:
Improvemechanical strengthVSAvoidoverall weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The patent applies local quality by using metal flanges only at specific locations where mechanical strength is needed (radial flanges for mounting support), while the majority of the annular wall remains as lightweight composite material. This localized reinforcement approach provides necessary strength without uniformly increasing the weight of the entire structure.

Inventive Principle:
Principle #3Local quality

2Strength

If the flanges are strongly thickened to counter tearings, then mechanical resistance is improved, but the casing becomes heavier

Engineering Contradiction:
Improvemechanical resistanceVSAvoidcasing weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The patent optimizes the flange thickness parameter to achieve the minimum necessary value for mechanical resistance rather than uniformly thickening all flanges. The composite-to-metal interface and controlled thickness allow the structure to achieve adequate strength while minimizing weight penalty.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple fixing means are used to attach blades to the casing, then reliability is improved, but stress concentrations increase

Engineering Contradiction:
Improveattachment reliabilityVSAvoidstress concentrations
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent segments the blade attachment system into modular fixing means distributed around the annular wall. Each fixing point is designed to handle specific loads, and the modular approach allows for optimized stress distribution. The segmentation enables reliable attachment while managing stress concentrations through proper spacing and design of individual fixing points.

Inventive Principle:
Principle #1Segmentation

4Reliability

If complex attachment mechanisms are used for blade fixing, then reliability is improved, but manufacturing cost and complexity increase

Engineering Contradiction:
Improveattachment reliabilityVSAvoidattachment mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes the composite nature of the annular wall (composite material with metal flanges) to simplify the attachment mechanism. The composite structure provides inherent strength and flexibility that reduces the need for overly complex attachment hardware. The metal flanges serve as integrated mounting surfaces that combine structural support with attachment functionality, reducing overall system complexity.

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

This solution reduces the cost and weight of the composite casing while enhancing mechanical strength by distributing forces and simplifying the manufacturing process, allowing for independent mass-strength optimization at different interfaces.

Implementation Method 1

The composite annular wall is made using a resin injection process by transfer into a mold in which a preform is enclosed

Methodology Applied
Scientific EffectResin injection:

Data Source

PatentEP2811121B1Composite casing for axial turbomachine compressor with metal flange
Publication Date: 2019.07.31 SAFRAN AERO BOOSTERS SA
  • EP2811121B1 patent drawingFigure 1~2
  • EP2811121B1 patent drawingFigure 3~4
  • EP2811121B1 patent drawingFigure 5~6

AI summary

The invention relates to an external annular housing (30) for a low-pressure axial turbomachine compressor. The housing (30) comprises an annular wall (32) made of an organic matrix composite material. The housing (30) includes an annular row of radially extending blades (26), the blades (26) having platforms (28) fixed to the annular wall (32). The housing (30) also includes a radial annular flange (36) having mounting means (48) adapted to allow the housing (30) to be mounted in the turbomachine. The annular flange (36) is attached to the annular wall (32) and defines an annular receiving area (43) for the blade platforms (28). The annular flange (36) is fixed to the annular wall by means of clamping means. The invention reduces the cost of manufacturing the casing and promotes force transmission between the annular flange and the blade platforms, which offers the advantage of reducing stresses in the annular wall.