Annular Acoustic Panel Fixation for Turbomachine Casing
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Solution Overview
Problem
Existing turbomachine acoustic insulation panels face issues with weight increase, potential damage to fan blades, acoustic impedance discontinuities, and difficult maintenance due to the use of numerous fixing screws and sectorized panels, as well as manufacturing tolerances in non-cylindrical casing walls.
Innovation Solution
A turbomachine casing with an annular one-piece acoustic insulation panel that uses dismountable projecting members and lugs for secure fixation without passing through the radial dimension of the panel, allowing for easy mounting and dismounting and adjustment for cylindricality defects, reducing weight and impedance discontinuities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If numerous fixing screws are used to secure sectorized acoustic panels, then the panels can be firmly fixed to the casing wall, but the weight of the turbomachine increases and the risk of fan blade damage increases
Solution Approach 1:
The patent merges multiple sectorized panels into a single annular one-piece acoustic insulation panel that covers the entire internal surface of the casing wall. This eliminates the need for numerous fixing screws by using a continuous panel structure secured with fewer fixing elements, thereby reducing weight while maintaining fixation reliability.
Solution Approach 2:
The patent extracts the fixing screws from the radial direction and repositions them to extend parallel to the longitudinal axis of the turbomachine. This extraction from the traditional radial mounting approach reduces the number of screws needed and eliminates the risk of screw loss or breakage damaging fan blades, while maintaining secure panel fixation.
2Reliability
If numerous fixing screws are used to secure sectorized acoustic panels, then the panels can be firmly fixed to the casing wall, but acoustic impedance discontinuities are created increasing noise levels
Solution Approach 1:
The patent merges multiple sectorized panels into a single annular one-piece acoustic insulation panel. This continuous panel structure eliminates the interface areas between sectors that cause acoustic impedance discontinuities, thereby reducing noise levels while maintaining secure fixation through fewer fixing elements positioned parallel to the longitudinal axis.
3Reliability
If hot-setting adhesive gluing is used to fix acoustic panels to the casing wall, then the panels are securely fixed, but the manufacturing process becomes time-consuming and panel replacement requires engine dismounting
Solution Approach 1:
The patent segments the fixation system into removable fixing members that can be independently accessed and manipulated. These fixing members extend parallel to the longitudinal axis, allowing panel installation and removal through the annular space without requiring engine dismounting, while maintaining secure fixation during operation.
Solution Approach 2:
The patent transforms the fixation system from a static permanent bond (hot-setting adhesive) to a dynamic removable connection. The fixing members can be engaged and disengaged along the longitudinal axis, enabling panel replacement during maintenance without engine dismounting, while providing secure fixation during normal operation.
4Ease of manufacture
If sectorized panels are used to cover the casing wall, then the panels can be manufactured and installed separately, but the interface areas between sectors create acoustic impedance discontinuities
Solution Approach 1:
The patent merges multiple sectorized panels into a single annular one-piece acoustic insulation panel manufactured as one continuous structure. This eliminates the interface areas between sectors that cause acoustic impedance discontinuities and noise, while the panel can still be installed as a single unit through the annular space.
5Ease of manufacture
If the casing wall has manufacturing tolerances resulting in non-cylindrical internal surface, then the wall can be manufactured more easily, but the acoustic panels cannot be properly mounted
Solution Approach 1:
The patent changes the orientation of the fixing members from radial (perpendicular to the casing wall) to axial (parallel to the longitudinal axis). This dimensional change allows the panel to be mounted along the length of the turbomachine, accommodating casings with non-cylindrical internal surfaces due to manufacturing tolerances, while maintaining secure fixation.
Data Source
AI summary
A turbomachine casing including a substantially cylindrical wall and an annular one-piece acoustic insulation panel mounted inside the wall, the panel including an annular surface that is radially external opposite a radially internal annular surface of the wall, wherein the wall includes on its internal angular surface first projecting members which bear axially against second projecting members belonging to the external annular surface of the panel and which are fixed to these second members in a dismountable manner.