Composite Turbomachine Vane Trailing Edge Design

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Solution Overview

Problem

Composite material vanes for aircraft turbomachines face challenges in achieving the required fibre volume ratio at the trailing edge, leading to mechanical property issues and aerodynamic performance degradation due to square protruding edges, which necessitates additional machining steps and increases production costs.

Innovation Solution

A composite vane design featuring a thermoplastic composite material covering element with a fibre fabric draped over the trailing edge, interposed between the first metal shield and the leading edge, which extends over and along the trailing edge to cover loose fibres and achieve the desired mechanical properties and rounded shape directly in the mould, eliminating the need for additional machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a fibrous preform is used to manufacture the vane, then the mass is reduced, but the fibre volume ratio at the trailing edge cannot be controlled, leading to poor mechanical properties

Engineering Contradiction:

Improvemass of vaneVSAvoidfibre volume ratio at trailing edge

Core Design Contradiction:

Weight of moving objectVSManufacturing precision

Solution Approach 1:

The preform is divided into two distinct parts: the main blade area with controlled fibre volume ratio, and the trailing edge protuberance with defaulting fibre volume ratio. This segmentation allows each part to be optimised independently - the main body maintains light weight while the protuberance is designed to be removed later to achieve the desired trailing edge properties.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The preform is intentionally designed with an extended trailing edge protuberance during the weaving stage, before manufacturing begins. This preliminary action anticipates the need for trailing edge correction and prepares the structure for subsequent removal of the protuberance, ensuring the final trailing edge achieves the required fibre volume ratio.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If the trailing edge is machined to remove the protuberance, then the fibre volume ratio is corrected, but square protruding edges are created that degrade aerodynamic properties

Engineering Contradiction:

Improvefibre volume ratio at trailing edgeVSAvoidtrailing edge shape

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

Instead of creating square edges through machining, the invention introduces a rounding element that provides curvature to the trailing edge. This element is positioned to round the corners and create a smooth, aerodynamic profile, eliminating recirculation areas and improving airflow characteristics while maintaining the corrected fibre volume ratio.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Shape

If the trailing edge is machined a second time to create a rounded shape, then aerodynamic properties are improved, but production costs increase due to extra manufacturing steps

Engineering Contradiction:

Improvetrailing edge shapeVSAvoidproduction efficiency

Core Design Contradiction:

ShapeVSProductivity

Solution Approach 1:

The rounding element is introduced during the initial preform preparation stage, before the main manufacturing process begins. This preliminary action ensures the rounded trailing edge shape is built-in from the start, eliminating the need for subsequent machining operations and associated costs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The rounding element is integrated into the preform structure and manufactured together with the main blade in a single RTM process. This merging of the rounding function into the primary manufacturing process eliminates separate machining steps, reducing production time and cost while maintaining aerodynamic quality.

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

This solution enhances mechanical properties, improves aerodynamic performance by achieving a rounded trailing edge, reduces production costs by eliminating extra machining steps, and simplifies manufacturing by integrating the covering element during resin injection, thereby minimizing non-conformities and increasing production efficiency.

Implementation Method 1

The preform is then heated to polymerise the resin and form the final part

Methodology Applied

Scientific EffectPolymerisation: Photopolymerisation

Implementation Method 2

The preform is therefore woven wider than necessary, then cut with a waterjet

Methodology Applied

Scientific EffectJet erosion: Jet Erosion

Data Source

PatentUS20230407754A1Composite vane for an aircraft turbomachine and method for the manufacture thereof

Publication Date: 2023.12.21 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A composite vane for a turbomachine, in particular an aircraft turbomachine, this vane including an aerofoil having a pressure side and a suction side connected together by a leading edge and by a trailing edge, the aerofoil been formed from a fibrous preform obtained by weaving fibres in three dimensions, which is embedded in a polymer matrix, the vane further including a first metal shield extending over and along the leading edge of the aerofoil, the vane further including at least one cover element extending over and along the trailing edge of the aerofoil.