Elastic Tube Support in Turbomachine Arms for Vibration Resistance

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Solution Overview

Problem

Turbomachine service tubes experience vibrations that lead to rapid fatigue and potential rupture due to natural frequency resonance, especially in large engines, where existing central support systems fail to provide sufficient contact with the longitudinal cavity walls, leading to robustness and safety issues.

Innovation Solution

A turbomachine assembly featuring a central support system with U-shaped elastic blades brazed to the tube, positioned equidistantly, which compresses to pass through the cavity and then relaxes to exert pressure on the walls, ensuring contact and reducing vibrations, using materials with specific stress-strain properties and dimensions to optimize frequency and assembly ease.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a central support system is added to stabilize the tube within the hollow arm, then vibration resistance is improved, but the complexity of the device increases

Engineering Contradiction:
Improvevibration resistanceVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The central support is divided into two separate elastic blades instead of a single monolithic structure. Each blade can independently deform and exert pressure on the cavity walls, providing stabilization while maintaining simplicity in manufacturing and assembly

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The elastic blades are designed with specific material properties (stress-strain curve between minimum and maximum stress curves in table A) and geometric parameters (U-shape configuration) that enable them to automatically adjust their pressure on the cavity walls based on the tube's position and vibration characteristics

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the central support is compressed to pass through the cavity opening, then ease of assembly is improved, but the structural integrity during assembly is worsened

Engineering Contradiction:
Improveassembly easeVSAvoidstructural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The central support transitions from a rigid structure to a dynamic, deformable structure during assembly. The elastic blades can be compressed to fit through the opening and then automatically rebound to their original shape, eliminating the need for permanent deformation or complex assembly mechanisms

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The elastic blades function as flexible elements that can temporarily deform during assembly and then recover their shape. This flexibility allows the support to pass through the cavity opening when compressed and then expand to provide stabilization, maintaining structural integrity throughout the process

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If the orthogonal section length of the central support is greater than the cavity width, then vibration stabilization is improved, but the difficulty of insertion is worsened

Engineering Contradiction:
Improvestabilization effectivenessVSAvoidinsertion difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The elastic blades are pre-compressed before insertion to reduce their orthogonal section length below the cavity width. This preliminary compression allows easy insertion, and once inside the cavity, the blades automatically rebound to their full length, providing effective stabilization without manual adjustment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The U-shaped elastic blades are designed to envelop the tube when expanded, creating a nested configuration where the support contains the tube. This nesting provides effective stabilization while the compressed state during insertion allows the larger expanded dimensions to pass through the smaller opening

Inventive Principle:
Principle #7Nested doll (Nesting)

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 assembly effectively reduces resonance vibrations by maintaining permanent contact with the cavity walls, enhancing the robustness and reliability of fluid conveyance between turbomachine parts, while simplifying assembly and reducing manufacturing costs.

Implementation Method 1

the elastic blades are brazed to the tube or linked to a support configured to be attached to the tube, in that each of the elastic blades has a U shape so that, once placed on the tube, the tube is extends into the hollow of the U formed by each of the blades

Methodology Applied
Scientific EffectElastic recovery: Elasticity

Implementation Method 2

the elastic blades are brazed to the tube or linked to a support configured to be attached to the tube

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP3601746B1Central support for auxiliary tubes with elastic return
Publication Date: 2022.01.12 SAFRAN AIRCRAFT ENGINES SAS
  • EP3601746B1 patent drawingFigure 1
  • EP3601746B1 patent drawingFigure 2
  • EP3601746B1 patent drawingFigure 3

AI summary

The invention relates to a turbomachine assembly comprising: - a casing comprising: - an internal hub (10), - an external ferrule (20) extending around and at a distance from the internal hub (10), - a hollow arm (30), provided with a longitudinal cavity (40) and connecting the internal hub (10) and the external ferrule (20), - a tube (50) configured to extend in the interior of the longitudinal cavity (40) of the hollow arm (30) of the casing and comprising a central support (60) comprising two elastic blades (61) and configured to exert a pressure on the wall (42) of the longitudinal cavity (40) when the tube (50) is extended in the interior of the longitudinal cavity (40); characterized in that the material(s) of the elastic blades (61) is (are) such that said elastic blades (61) have a stress curve between the minimum and maximum stress curves of table A.