Single-Piece Annular Turbine Casing Panel Acoustic Insulation

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Solution Overview

Problem

Existing turbine engine acoustic insulation panels face issues with weight increase, risk of damaging fan blades, acoustic impedance discontinuities, and difficulty in maintenance due to sectorized designs and adhesive bonding, which complicates panel replacement and positioning.

Innovation Solution

A turbine engine casing with a single-piece annular acoustic insulation panel featuring sliding and centering mechanisms, including radially extending portions with nut-and-bolt assemblies and centering pegs, allows for easy installation, removal, and accurate positioning without statically indeterminate connections, maintaining acoustic efficiency and reducing weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sectorized panels are used with multiple fastener screws, then the panel can be securely fastened to the casing wall, but the weight of the turbine engine increases and the risk of damaging fan blades increases

Engineering Contradiction:

Improvepanel fastening securityVSAvoidturbine engine weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The panel is divided into multiple sectorized sections that can be independently fastened, allowing secure attachment with fewer fasteners per section while maintaining overall reliability. Each sector can be fastened separately, reducing the total number of fasteners needed compared to a single large panel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple fastening functions are combined into integrated fastening structures that secure the panel to the casing wall in a single operation, reducing the number of separate fastener screws needed and thereby reducing weight while maintaining security.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If sectorized panels with multiple fastener screws are used, then the panel can be securely fastened, but the interface zones create acoustic impedance discontinuities that increase noise levels

Engineering Contradiction:

Improvepanel fastening securityVSAvoidnoise levels

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The panel is designed as a continuous structure that merges the acoustic insulation function across the entire panel surface, eliminating the interface zones between sectors that create acoustic impedance discontinuities. This continuous structure reduces noise levels while maintaining fastening security through integrated fastening systems.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If adhesive bonding is used to attach the panel, then the panel can be securely attached, but the process takes several hours in an autoclave and the engine must be removed for replacement

Engineering Contradiction:

Improvepanel attachment securityVSAvoidpanel installation and replacement time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The adhesive bonding process is replaced with a mechanical fastening system that allows the panel to be attached and removed without requiring autoclave treatment. The mechanical fasteners provide secure attachment while enabling quick installation and replacement, eliminating the need for time-consuming adhesive curing processes and engine removal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The fastening system is designed to be dynamically removable and reconfigurable, allowing the panel to be quickly detached and reattached without permanent adhesive bonds. This dynamic fastening capability enables maintenance operations to be performed without removing the engine, significantly reducing loss of time.

Inventive Principle:

Principle #15Dynamics

4Ease of repair

If elastically deformable tabs are used for fastening, then the panel can be easily removed without removing the engine, but the tabs may deform or crack under mechanical or thermal stresses

Engineering Contradiction:

Improvepanel removabilityVSAvoidtab structural integrity

Core Design Contradiction:

Ease of repairVSReliability

Solution Approach 1:

The fastening tabs are constructed from composite materials that combine the flexibility needed for easy removal with the strength required to withstand mechanical and thermal stresses. This composite construction maintains structural integrity while preserving the ease of removal capability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The tab design incorporates parameter changes in its geometry and material properties to optimize both removability and stress resistance. The tabs are designed with specific dimensional characteristics and material selections that allow elastic deformation for removal while maintaining integrity under operational stresses.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9611863B2Turbine engine casing

Publication Date: 2017.04.04 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A turbine engine casing, including a substantially cylindrical wall and a single-piece annular panel for acoustic insulation mounted radially inside the wall, is provided. The panel includes a radially outer annular surface fitted with upstream and downstream first projecting members respectively arranged in the upstream and downstream portions of the radially outer annular surface of the panel. The wall includes a radially inner annular surface fitted with upstream and downstream second projecting members that are releasably fastened respectively to the upstream and downstream first projecting members.