Leaf Spring Flap Seal Arrangement for Turbomachine Thermal Movement

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Solution Overview

Problem

Existing sealing arrangements for turbomachines, particularly gas turbines, face challenges in effectively sealing gaps between components, especially under thermal movements and in maintaining efficient assembly and operation.

Innovation Solution

A sealing arrangement featuring a pivotably mounted flap and a leaf spring with V or U-shaped legs, which is designed to partially or temporarily seal annular gaps around the machine axis, utilizing a common component for both sealing and structural support, and incorporating positioning elements for improved kinematics and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealing arrangement uses a flap and leaf spring to seal gaps between components, then sealing effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvesealing effectivenessVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the sealing flap and leaf spring into an integrated assembly where the leaf spring serves both as a mounting structure and as the actuating mechanism. The first leg of the leaf spring forms a bearing surface for the flap, while the second leg provides pre-tensioning, merging multiple functions into a single component system that reduces overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The leaf spring performs multiple functions simultaneously: it provides pre-tensioning force, forms a bearing surface for the flap, acts as a mounting structure, and compensates for thermal movements. This multi-functionality reduces the number of separate components needed, thereby improving sealing effectiveness while managing device complexity.

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

2Adaptability or versatility

If the sealing arrangement is designed to compensate for thermal movements, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvecompensation for thermal movementsVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The flap is designed to be movable relative to the first component, allowing it to dynamically adjust its position in response to thermal expansion or contraction of the sealed components. The leaf spring provides flexible pre-tensioning that maintains sealing contact despite these movements, enabling the system to adapt to thermal changes without requiring complex adjustment mechanisms.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If the projection of the contact area lies within the bearing surface, then ease of manufacture is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveease of manufactureVSAvoidmanufacturing precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The leaf spring is pre-tensioned during assembly to establish the correct positioning and contact forces before the sealing arrangement enters service. This preliminary action ensures that the flap is properly aligned and contacted by the first component, reducing the need for high-precision manufacturing tolerances while maintaining sealing effectiveness.

Inventive Principle:
Principle #10Preliminary action

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 enhances the operational behavior of turbomachines by effectively separating fluid spaces, compensating for thermal movements, and simplifying assembly and disassembly, while providing a stable and compact sealing mechanism.

Implementation Method 1

a pre-tensioning force is exerted by the leaf spring in a state here referred to without limitation of generality as an assembly state, in which the flap and the second component do not contact each other

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

relative movements between the first and second components, especially those caused by thermal expansion, to be at least partially compensated

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3330490B1Turbo machines seal arrangement
Publication Date: 2024.05.15 MTU AERO ENGINES GMBH
  • EP3330490B1 patent drawingFigure 1~3
  • EP3330490B1 patent drawingFigure 4~5

AI summary

The present invention relates to a sealing arrangement for a turbomachine, in particular a gas turbine, having a first component (10A, 10B), a second component (20), a flap (30) for sealing a gap between the first and second components, and a leaf spring with a first leg (41) and a second leg (42), wherein in an assembly state in which the flap and second component do not contact each other, a projection of a contact area (11) of the first component (10A, 10B) against which the first leg (41) via the flap (30), perpendicular to a contact line (K) through at least two contact points of the first leg (41) with the flap (30) at least partially within a bearing surface (A) of the first component (10A, 10B) against which the second leg (42) of the prestressed leaf spring is supported.