Axial Turbomachine Rotor Drum with Peripheral Retention Surfaces

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Solution Overview

Problem

Existing axial turbomachine compressor drums face issues with material weight, cost, reduced rigidity due to discontinuities, and complex machining of fixing surfaces, particularly with annular cells that increase deformations and complicate machining.

Innovation Solution

The drum design eliminates annular discs, features retention surfaces forming angles between 30° and 60° with the axis, with annular ribs and abradable material layers for reduced material usage and simplified machining, and includes notches and O-ring seals for improved stability and sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If annular cells are used to fix rotor blades, then blade fixation is achieved, but material weight increases and drum rigidity decreases

Engineering Contradiction:
Improveblade fixationVSAvoiddrum weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The invention extracts and eliminates the annular cells from the drum structure, retaining only the essential fixation function through retention surfaces on the drum periphery. This removal of unnecessary material directly reduces drum weight while maintaining blade fixation capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of providing fixation structure throughout the entire drum wall, the invention applies fixation surfaces only at the specific locations where blades need to be retained. This localized approach minimizes material usage while ensuring adequate fixation where needed.

Inventive Principle:
Principle #3Local quality

2Reliability

If annular cells are used to fix rotor blades, then blade fixation is achieved, but drum rigidity decreases due to material discontinuity

Engineering Contradiction:
Improveblade fixationVSAvoiddrum rigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

By removing the annular cells that created discontinuities in the drum wall, the invention restores the continuity of the drum structure. The retention surfaces are integrated into the drum periphery without creating through-wall discontinuities, thereby maintaining drum rigidity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the fixation function directly into the drum wall structure through retention surfaces, eliminating the need for separate annular cell structures. This integration maintains the structural continuity of the drum while providing adequate blade retention.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If annular cells with fixing surfaces are used, then blade retention is achieved, but machining complexity increases due to difficult access

Engineering Contradiction:
Improveblade retentionVSAvoidmachining complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts the fixation surfaces from the interior of annular cells and places them on the accessible periphery of the drum. This external placement of retention surfaces allows for straightforward machining operations without the need to access difficult-to-reach interior surfaces.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of providing fixation surfaces inside closed annular cells (internal configuration), the invention inverts the approach by providing retention surfaces on the external periphery of the drum (external configuration). This inversion makes the surfaces easily accessible for machining and inspection.

Inventive Principle:
Principle #13The other way round (Inversion)

4Strength

If traditional drum designs are used, then structural integrity is maintained, but material usage and cost increase

Engineering Contradiction:
Improvestructural integrityVSAvoidmaterial usage
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The invention extracts and removes the excessive material in the form of annular cells from the drum structure, retaining only the minimum necessary material for structural integrity and blade fixation. This material reduction directly lowers both weight and manufacturing cost.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the structural parameters of the drum by transitioning from a thick-walled design with annular cells to a thin-walled design with integrated retention surfaces. This parameter change optimizes the material usage while maintaining adequate structural strength.

Inventive Principle:
Principle #35Parameter changes

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 design simplifies machining, reduces material weight, enhances rigidity, and improves blade fixation stability without increasing material usage, leading to a more durable and efficient turbomachine compressor drum.

Implementation Method 1

said ribs being configured to cooperate by abrasion with annular layers of abradable material

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 2

an annular groove open radially outwards configured to receive a preferentially O-ring seal intended to be pressed against the platforms of the blades under the effect of centrifugal force during rotation of the drum

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2762681B1Rotor drum of an axial turbomachine and corresponding turbomachine
Publication Date: 2017.09.06 SAFRAN AERO BOOSTERS SA
  • EP2762681B1 patent drawingFigure 1~2
  • EP2762681B1 patent drawingFigure 3~4
  • EP2762681B1 patent drawingFigure 5~6

AI summary

The drum has a wall (30) rotated about a rotation axis (14) of a rotor, where the wall forms an annular body (36). A row of rotor blades (24) comprises two annular retaining surfaces (38, 42) that are arranged on an outer surface of the wall. The retaining surfaces are diverged from one another to form a profile, where the profile is radially outwards from the outer surface of the wall. The wall is extended in a straight line along the two retaining surfaces between upstream and downstream ribs (32).