Turbomachine Nozzle Vane Liners for Thermal Stress Relief

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Solution Overview

Problem

The connection zones between the liners and the high or low pressure distributor in turbomachines are prone to stress and cracking due to temperature changes, leading to potential ruptures and maintenance costs, as the materials used for the distributor and liners expand differently.

Innovation Solution

The distributor blade design features interlacing jackets that are mechanically independent of the blade body, with a system of lugs and orifices allowing the jackets to connect independently, eliminating the need for direct attachment to the blade or distributor, thus avoiding stress from material expansion differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the sleeves are directly attached to the distributor using welding or brazing, then the sleeves are mechanically connected and secured within the distributor, but the connection zones are subject to significant stress and cracking due to differential thermal expansion between different materials

Engineering Contradiction:

Improvemechanical connection strengthVSAvoidresistance to thermal stress and cracking

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The blade is segmented into distinct functional zones: the blade body, the cooling sleeves, and the interlacing connection system. This segmentation allows each component to be optimized independently and connected through a mechanism that accommodates differential thermal expansion, resolving the contradiction between mechanical strength and thermal stress resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The interlacing system acts as an intermediary between the blade body and the cooling sleeves. This intermediate structure provides a mechanical connection that accommodates differential thermal expansion through its design (interlocking lugs and orifices), eliminating direct welding or brazing between dissimilar materials and preventing stress concentration at the connection zones.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If the sleeves are made from materials with different expansion coefficients than the distributor, then the cooling performance is optimized, but the connection zones experience significant stress during temperature changes

Engineering Contradiction:

Improvecooling efficiencyVSAvoidthermal expansion stress

Core Design Contradiction:

TemperatureVSStress or pressure

Solution Approach 1:

The invention changes the connection mechanism from rigid welding/brazing to a flexible interlacing system that can accommodate parameter changes (thermal expansion) of the sleeve materials. This allows the use of materials with different expansion coefficients for optimal cooling while preventing stress accumulation through the compliant connection design.

Inventive Principle:

Principle #35Parameter changes

3Strength

If the sleeves are embedded and mechanically connected to the distributor, then the structural integrity is improved, but maintenance requires complete distributor replacement when cracks occur

Engineering Contradiction:

Improvestructural integrityVSAvoidmaintenance complexity

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The segmentation of the cooling system into independently replaceable sleeves connected through an interlacing system allows the sleeves to be maintained or replaced without replacing the entire distributor. This resolves the contradiction by maintaining structural integrity through the interlacing connection while enabling selective maintenance of only the worn components.

Inventive Principle:

Principle #1Segmentation

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 prevents mechanical stress at the connection zones, reducing the risk of cracking and enabling the liners to expand without causing damage, simplifying maintenance and reducing downtime and costs.

Implementation Method 1

with a system of lugs and orifices allowing the jackets to connect independently, eliminating the need for direct attachment to the blade or distributor

Methodology Applied

Scientific EffectMechanical interlocking: Mechanical Fastener

Implementation Method 2

the materials used for the distributor and liners expand differently... enabling the liners to expand without causing damage

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4111036B1Nozzle vane for turbomachine, corresponding high or low pressure nozzle for turbomachine, turbomachine and method of manufacturing a vane of a nozzle for turbomachine

Publication Date: 2023.12.20 SAFRAN AIRCRAFT ENGINES SAS

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AI summary

One aspect of the invention relates to a nozzle blade (100) for a turbine engine comprising a blade body (110) in which at least one through-cavity (122) is provided extending between an inner end (111) of the blade and an outer end (112) of said blade and housing, respectively, a first and a second liner (220, 240), the first liner (220) extending along a trailing edge (116) of the blade, the second liner (240) extending along a leading edge (117) of said blade, wherein each of the first and second liners (220, 240) comprise an intertwining system (251-254) suitable for bonding the first liner (220) to the second liner (240), independently of the blade body.