Leaf Spring Sealing Blade Holding Device for Turbomachine

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Solution Overview

Problem

Existing blade sealing systems in turbomachines face issues with asymmetry, plasticization, and complexity in manufacturing and assembly due to the use of holding devices that require multiple bends and rivets, leading to potential leakage and aerodynamic disturbances.

Innovation Solution

A leaf spring-based holding device with a C-shape and double abutment on a single blade, providing improved stress distribution and flexibility, which reduces the risk of plasticization and eliminates the need for balancing and additional fasteners, allowing for efficient damping of pressures and vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a holding device with multiple bends and rivets is used to plate adjacent blades together, then sealing reliability is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvesealing reliabilityVSAvoidholding device complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The holding device is divided into separate functional elements: a U-shaped support structure with first and second arms that can independently engage with different blades, and a distinct holding member that plates the blades together. This segmentation allows each component to be optimized and assembled separately, reducing overall complexity while maintaining sealing reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A joint cover is introduced as an intermediary element between the holding device and the blades. The joint cover simplifies the assembly process by providing a standardized interface, eliminating the need for multiple rivets and complex bending operations while ensuring reliable plateing of adjacent blades.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a holding device requiring multiple bends is used, then sealing capability is improved, but manufacturing precision and assembly difficulty worsen

Engineering Contradiction:

Improvesealing capabilityVSAvoidmanufacturing and assembly precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The U-shaped support structure is pre-formed with predetermined curvature and dimensions during manufacturing. The first and second arms are already positioned at the correct angles and distances from the support portion, eliminating the need for complex bending operations during assembly and ensuring consistent sealing capability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The holding device uses standardized components that can be mass-produced using identical tooling and processes. The U-shaped support structure and holding member are designed as repeatable parts that can be assembled using the same procedure for each sealing location, improving manufacturing precision and reducing assembly variability.

Inventive Principle:

Principle #26Copying

3Reliability

If adjacent blades are plated together using traditional holding devices, then sealing is improved, but asymmetry and offset between sectors occur

Engineering Contradiction:

Improvesealing performanceVSAvoidsector symmetry

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The U-shaped support structure is designed with asymmetric arm configurations that adapt to the specific geometry of each blade sector. The first arm engages with a first blade at a predetermined angle, while the second arm engages with a second blade at a corresponding angle, maintaining symmetry across all sectors while accommodating individual blade variations.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The holding device allows for adjustable parameters including the spacing between the first and second arms, the curvature radius of the U-shaped support, and the engagement positions on the blades. These parameters can be optimized for each sector to maintain sectorial symmetry and prevent offset while ensuring effective plateing of adjacent blades.

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

The solution enhances the reliability and service life of the sealing system by maintaining blade position, reducing plasticization, eliminating asymmetry and offset, and simplifying manufacturing and assembly, thereby improving engine performance and reducing aerodynamic disturbances.

Implementation Method 1

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

allowing for efficient damping of pressures and vibrations

Methodology Applied

Scientific EffectDamping: Damping

Data Source

PatentUS11268395B2Turbomachine module equipped with a holding device for sealing blades

Publication Date: 2022.03.08 SAFRAN AIRCRAFT ENGINES SAS

AI summary

Turbomachine modules, for example for an aircraft, include a turbine nozzle having several sectors (S), each sector having guide vanes extending between inner and outer platform elements, at least one of the platform elements of each sector carrying, on the one hand, at least one sealing blade configured to ensure fluid sealing between the platform element and the adjacent structural element, and, on the other hand, a device configured to hold the at least one sealing blade in a sealing position. The device includes a leaf spring having a middle portion fixed to the platform element, and opposite end portions which are supported on the sealing blade carried by the platform element.