Inflatable Bladder Sealing for Turbomachine Stator Blades

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Solution Overview

Problem

The existing methods for assembling a turbomachine stator stage, particularly in aircraft engine turbo machines, are costly and time-consuming due to the need for specialized tools and labor-intensive processes, and they fail to ensure consistent quality of the sealing joints between blades and shrouds.

Innovation Solution

A method and device utilizing inflatable bladders to form retaining surfaces for sealing material, allowing for efficient and uniform sealing between blades and shrouds, with the bladders being applied between neighboring blades and inflated to cover the entire opening, ensuring a strong and airtight connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If paste-like sealing material is used to seal blades to the stator inner shell, then a bonding joint is formed, but the process is expensive and time-consuming

Engineering Contradiction:
Improvesealing qualityVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The bladder is inflated before applying the sealing material to pre-form the retention surface, ensuring proper sealing geometry is established in advance. This preliminary action prevents material leakage and ensures consistent sealing quality while reducing assembly time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The inflatable bladder acts as an intermediary tool that creates the retention surface for sealing material. It mediates between the blade opening and the sealing material, providing a controlled form that ensures consistent sealing without requiring complex specialized tooling for each blade.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If counter-forms are installed individually between blades to seal openings, then the seal creation is facilitated, but the assembly becomes time-consuming

Engineering Contradiction:
Improveseal creation easeVSAvoidmounting and dismounting time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The inflatable bladder device is designed to be universally applicable across different blade configurations and stator designs. A single bladder can be inflated to accommodate various opening sizes and shapes, eliminating the need for multiple specialized counter-forms for different blade types.

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

Solution Approach 2:

The bladder transitions from a deflated state (easy to install) to an inflated state (provides sealing function). This dynamic transformation allows the same component to be quickly deployed and removed without complex mounting procedures, significantly reducing assembly time while maintaining sealing effectiveness.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the tooling is adapted to each stator design based on blade spacing and profile, then the seal is effective, but the device complexity increases

Engineering Contradiction:
Improvesealing effectivenessVSAvoidtooling adaptation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bladder's physical parameters (volume, pressure, shape) are adjusted during inflation to adapt to different blade openings. This allows a single standardized bladder design to accommodate various blade spacings and profiles without requiring custom tooling for each stator configuration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The bladder is made of flexible material that can deform and adapt to different opening geometries. This flexibility allows the same bladder to conform to various blade profiles and spacing arrangements, eliminating the need for rigid, design-specific counter-forms while maintaining effective sealing.

Inventive Principle:
Principle #30Flexible shells and thin films

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 approach speeds up the assembly process while harmonizing the quality of connecting joints, reducing costs and improving the consistency of the sealing process, ensuring effective sealing and airtightness between the blades and shrouds.

Implementation Method 1

The device includes an elongated support (26) connected to a pressurized gas source and distributing said gas into each bladder

Methodology Applied
Scientific EffectGas compression and expansion: Compression

Data Source

PatentEP2979815B1Application of bonding seal on a guide vane stage by means of inflatable bladders
Publication Date: 2019.05.15 SAFRAN AERO BOOSTERS SA
  • EP2979815B1 patent drawingFigure 1~3
  • EP2979815B1 patent drawingFigure 4~6

AI summary

The invention relates to a method for assembling a turbomachine stator stage (2), said stage comprising an inner shell (4), an outer shell, and blades (8) extending radially between the inner (4) and outer shells, the method comprising at least the following essential step: (b) applying at least one inflatable bladder (12) against at least one opening (14) between a blade (8) and one (4) of the inner (4) and outer shells on the face (16) of the shell (4) opposite the application face (18) of a sealing material, so as to form one or more retention surfaces (22) for said sealing material (20). The invention also relates to an assembly device for implementing the method.