Turbomachine Ring Assembly Thermal Expansion Fixing

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Solution Overview

Problem

Differential thermal expansions between heat exchangers and their mounting shells in turbomachines lead to mechanical stresses and complex assembly challenges, particularly when the heat exchanger material has a higher coefficient of thermal expansion than the shell material.

Innovation Solution

The implementation of a fixing system with radially arranged plates and a removable support element that allows tangential sliding and deformation, facilitating pre-assembly and ensuring secure attachment while accommodating thermal expansion, using a rail with L-shaped sections and elastic means for radial retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the heat exchanger is made of material with higher coefficient of thermal expansion than the shell, then heat exchange efficiency is improved, but mechanical stresses increase due to differential thermal expansion

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidmechanical stresses
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The invention changes the physical state and parameters of the connection system by introducing elastic means that can deform radially, allowing the connection to adapt to thermal expansion differences while maintaining secure attachment. The elastic component transforms the rigid connection into a flexible one that accommodates parameter changes during thermal cycling.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fixing system transitions from a static rigid connection to a dynamic system where the elastic means can deform and recover. This dynamic capability allows the connection to accommodate differential thermal expansion between the heat exchanger and shell, reducing mechanical stresses while maintaining operational efficiency.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If rigid fixing means are used to secure the heat exchanger, then attachment stability is improved, but thermal expansion accommodation deteriorates

Engineering Contradiction:
Improveattachment stabilityVSAvoidthermal expansion accommodation
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The elastic means introduces parameter changes in the form of radial deformation capability. This allows the connection to maintain stability through elastic recovery while adapting to thermal expansion variations, combining both rigid stability and flexible adaptability in a single connection system.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fixing system incorporates dynamic elements through the elastic means that can deform and recover radially. This dynamic characteristic enables the connection to maintain stability during operation while adapting to thermal expansion differences, resolving the contradiction between rigidity and flexibility.

Inventive Principle:
Principle #15Dynamics

3Stress or pressure

If complex fixing systems are implemented to accommodate thermal expansion, then stress reduction is improved, but assembly complexity increases

Engineering Contradiction:
Improvemechanical stressesVSAvoidassembly complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The invention merges multiple functions into a single integrated elastic means that provides both stress accommodation and secure attachment. By combining the expansion compensation function with the fixing function in one component, the system reduces overall complexity while maintaining stress reduction capabilities.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The elastic means serves multiple functions simultaneously: it accommodates thermal expansion, provides secure attachment, and reduces mechanical stresses. This multi-functionality eliminates the need for separate components for each function, simplifying the overall assembly while achieving stress reduction goals.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Strength

If the heat exchanger is firmly attached to prevent radial movement, then vibration transmission is improved, but thermal expansion accommodation deteriorates

Engineering Contradiction:
Improvevibration transmissionVSAvoidthermal expansion accommodation
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The elastic means enables parameter changes in the form of radial deformation to accommodate thermal expansion. This allows the connection to maintain strong attachment for vibration transmission while adapting its physical state to accommodate thermal expansion differences between components.

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 solution simplifies the assembly of heat exchangers, reduces mechanical stresses due to thermal expansion, and ensures stable attachment, preventing radial movement and vibration transmission, thereby enhancing the longevity and operational efficiency of the heat exchanger.

Implementation Method 1

the differences in thermal expansion between the shell 14 and the material of the heat exchanger 12 can weaken the connections between the heat exchanger 12 and the shell

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

elastic means for retaining the rail in the radial direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3857031B1Ring assembly for turbomachine and process to mount such an assembly
Publication Date: 2024.08.21 SAFRAN AIRCRAFT ENGINES SAS
  • EP3857031B1 patent drawingFigure 1~2
  • EP3857031B1 patent drawingFigure 3~6

AI summary

The invention concerns an annular assembly for a dual flow turbine engine having a longitudinal axis (A) and comprising a housing (12) comprising an annular shroud (14), one face of which supports a piece of annular equipment, a plurality of attachment means (18) for attaching the equipment to the annular shroud (14) being distributed around the longitudinal axis (A) and allowing the equipment (16) a degree of freedom in the tangential direction relative to the annular shroud (14), characterised in that each attachment means (18) comprises a rail (20) secured to the annular equipment (16) and arranged radially between a first radially inner plate (22) and a second, radially outer plate (24) and capable of sliding in the tangential direction between the first plate (22) and the second plate (24), and in that a removable support element (56) is securely connected to the annular shroud and to the first plate (22) and the second plate (24).