Integrated Ejection Tube for Turbomachine Ventilation

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Solution Overview

Problem

Vibrations and thermal differences cause cracking between the central ventilation tube and the interior tubular structure in turbomachines, leading to damage in the evacuation system due to static and vibratory solicitations.

Innovation Solution

Integration of the interior tubular structure and the central ventilation tube as a single piece, with a cylindrical tube design featuring a narrowing section and an extension tube linked by welding, manufactured using laser fusion on a powder bed, allowing for a unified structure that reduces stress points and enhances durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the central ventilation tube and inner tubular structure are made as two independent parts in contact, then the manufacturing and assembly are simpler, but cracks occur due to vibrations and temperature differences

Engineering Contradiction:
Improvecrack resistanceVSAvoidstructure integration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the central ventilation tube and inner tubular structure into a single integral component. The inner tubular structure is formed as one piece with the central tube, eliminating the interface between two separate parts. This integration removes the source of cracking that occurred at the contact interface between independent parts, directly resolving the reliability issue while accepting increased manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the inner tubular structure is integrated into the tube, then cracking is minimized, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs additive manufacturing (3D printing) technology to manufacture the integrated structure. This manufacturing method enables the creation of complex integral geometries that would be difficult or impossible to produce using traditional manufacturing processes. By changing the manufacturing approach from conventional methods to additive manufacturing, the patent achieves structural integrity through integration while managing the complexity of production.

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If the tube wall thickness is reduced to minimize material usage, then weight is reduced, but the structure becomes more susceptible to cracking under stress

Engineering Contradiction:
Improvetube weightVSAvoidcrack resistance
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The integral design of the inner tubular structure merged with the central ventilation tube creates a unified load-bearing structure. This merging distributes mechanical stresses and thermal gradients across the entire integrated component rather than concentrating them at interfaces between separate parts. The continuous material flow in the integral structure provides inherent crack resistance even with reduced wall thickness, as there are no discrete joints or contact surfaces where cracks can initiate and propagate.

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

The solution effectively minimizes cracking and damage by providing a unified, stress-reduced structure that maintains the integrity of the turbomachine's air evacuation system, ensuring reliable operation and extended lifespan.

Implementation Method 1

The invention also relates to a method of manufacturing an upstream part of an air evacuation system as presented previously, by laser fusion on a powder bed.

Methodology Applied
Scientific EffectLaser fusion: Laser

Implementation Method 2

During said manufacturing process, laser melting may take place from the upstream end to the downstream end.

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4314517B1Ejection tube integrated into a central ventilation tube
Publication Date: 2025.02.12 SAFRAN AIRCRAFT ENGINES SAS
  • EP4314517B1 patent drawingFigure 1~2
  • EP4314517B1 patent drawingFigure 3a~3c
  • EP4314517B1 patent drawingFigure 4a~4b

AI summary

The present invention relates to an upstream part of an air evacuation system for a turbomachine. The upstream part comprises a tube with an upstream end and a downstream end, an inner tubular structure situated inside said tube and configured to form a narrowing of its cross section there. The inner tubular structure is integrally formed with the tube at the downstream end of the tube and is freely suspended at the upstream end of the tube. The invention also relates to a turbomachine with a device for evacuating air from the bearing chambers, in which turbomachine the air is conducted towards the outside of the turbomachine by said air evacuation system. A method for manufacturing the air evacuation system is also presented.