Axial Turbomachine Compressor Drum with Mixed Blade Fixation

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Solution Overview

Problem

Axial turbomachine rotors experience vibrations and require complex, costly machining, resulting in a massive and heavy architecture that is difficult to analyze and dampen.

Innovation Solution

The rotor drum features an outer surface with annular ribs for sealing, a π-shaped profile, and blades welded to a raised platform, eliminating freedom of movement between the wall and vanes, and using a one-piece assembly of the first row blades and platform, made from metallic materials like titanium, to enhance rigidity and reduce weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If rotor blades are fixed by feet inserted into annular grooves, then assembly is simple, but vibrations increase and manufacturing becomes complex and costly

Engineering Contradiction:

Improveassembly simplicityVSAvoidmanufacturing complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The rotor assembly is segmented into modular components: blades with feet, annular grooves in the drum, and retention rings. This segmentation allows independent manufacturing of each component and simplified assembly, while the grooves and retention mechanisms provide vibration damping without requiring complex integrated machining

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The feet inserted into annular grooves act as intermediary elements between the blades and the drum. These intermediaries provide both mechanical retention and vibration isolation, eliminating the need for complex direct attachment methods while maintaining assembly simplicity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If rotor blades are fixed by feet inserted into annular grooves, then assembly is simple, but manufacturing becomes complex and costly

Engineering Contradiction:

Improveassembly simplicityVSAvoidmanufacturing cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

By dividing the rotor into separate manufacturable components (blades, drum, retention rings) that can be produced using standard machining processes, the overall manufacturing cost is reduced despite the modular assembly requirement

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of machining complex integrated blade attachments directly into the drum, the solution inverts the approach by providing detachable feet that fit into grooves, making both the blades and drum simpler to manufacture individually

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If rotor blades are fixed by feet inserted into annular grooves, then assembly is simple, but the rotor structure becomes massive and heavy

Engineering Contradiction:

Improveassembly simplicityVSAvoid rotor weight

Core Design Contradiction:

Ease of operationVSWeight of moving object

Solution Approach 1:

The drum structure utilizes thin-walled construction with strategically placed annular grooves and retention rings, replacing massive rigid structures. This allows the rotor to maintain structural integrity and vibration resistance while significantly reducing overall weight

Inventive Principle:

Principle #30Flexible shells and thin films

4Ease of operation

If rotor blades are fixed by feet inserted into annular grooves, then assembly is simple, but vibrations increase and are difficult to analyze and dampen

Engineering Contradiction:

Improveassembly simplicityVSAvoidvibrations

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The annular grooves and retention ring configuration are designed beforehand to provide vibration cushioning. The geometric arrangement of grooves and the compliance of the feet-groove interface inherently dampen vibrations before they can propagate through the rotor structure

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The feet-groove interface, which could be seen as a source of vibration, is designed to convert harmful vibrations into beneficial damping effects through controlled compliance and friction, transforming the potential harm into a vibration reduction mechanism

Inventive Principle:

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

Data Source

PatentEP2818635B1Drum of axial turbomachine compressor with mixed fixation of blades

Publication Date: 2019.04.10 SAFRAN AERO BOOSTERS SA

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AI summary

The invention relates to a rotor drum (40) of a low-pressure axial turbomachine compressor. The drum (40) comprises a wall (42) that is generally symmetrical in revolution about its axis (14) and has a generally curved profile. The wall (42) is configured to support several rows of blades (24, 26, 28). A first row of blades (24) is formed by an annular platform (46) integrally formed with the wall (42) at the apex of its profile relative to the axis (14); and a second row of blades (26), directly downstream of the first (24), and a third row of blades (28), directly upstream of the first (24), are formed by one or more blade retention grooves (54) formed on the wall. The blades of the first row (24) and the drum form a single unit, which eliminates certain vibrations. The blade anchoring is hybrid or mixed. This rotor can be mounted in a housing with rectifiers forming bushings.