Molded Abradable Seal Segments for Turbomachine Casing
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Solution Overview
Problem
The manufacturing and maintenance of abradable ring seals for turbomachines, particularly aircraft engines, are inefficient due to high costs, long times, poor reproducibility, and health/safety concerns associated with manually applying and curing pasty abradable materials, which also require extensive downtime for maintenance and repair.
Innovation Solution
A molded piece of abradable material made from a mixture of epoxy resin and crosslinking agent, incorporating bisphenol-A-epichlorhydrin or bisphenol-F-epichlorhydrin, and hollow glass spheres, is produced in a curved shape to fit within the turbomachine casing, allowing for rapid, cost-effective, and reproducible manufacturing and repair with improved mechanical strength and reduced defect risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pasty abradable material is manually applied to the stator inner surface, then the abradable coating can be formed, but the manufacturing process becomes tedious, expensive, and time-consuming with poor reproducibility
Solution Approach 1:
The patent changes the physical state of the abradable material from a soft paste to a molded solid form. This parameter change allows the material to be pre-formed with precise dimensions and geometry, eliminating manual application variability and enabling consistent, reproducible manufacturing while significantly reducing application time and labor requirements.
Solution Approach 2:
The abradable material is pre-formed into molded pieces with the exact shape and dimensions needed before installation. This preliminary action eliminates the need for manual application and on-site curing operations, improving both productivity and quality reproducibility by ensuring consistent material properties before the material is even installed in the engine.
2Reliability
If manual application of pasty material is used, then the abradable track can be formed, but health and safety risks increase due to hygiene precautions required
Solution Approach 1:
The patent extracts the material application process from the installation process by providing pre-formed molded pieces. This eliminates direct operator contact with uncured resinous materials, removing the health and safety hazards associated with manual paste application while maintaining product quality through controlled factory manufacturing conditions.
3Ease of repair
If maintenance operations involve removing damaged material and reapplying new material, then the abradable track can be repaired, but the engine must be immobilized for extended periods
Solution Approach 1:
The patent divides the abradable ring seal into replaceable segmental pieces that can be independently removed and replaced. This segmentation allows for rapid repair operations where damaged segments are simply swapped out rather than requiring complete removal and reapplication of material, dramatically reducing engine downtime while maintaining full repair capability.
Solution Approach 2:
The molded abradable pieces are designed as replaceable components that can be quickly swapped during maintenance. Rather than performing complex removal and reapplication operations, the system allows for rapid replacement of worn segments, treating the abradable material as a consumable component that simplifies maintenance procedures and reduces downtime.
4Ease of manufacture
If pasty material is used and pressed under a roller, then the material can be applied to the support, but the process remains complex and time-consuming
Solution Approach 1:
The abradable material geometry and dimensions are predetermined and pre-formed during molded piece fabrication. This preliminary action eliminates the need for on-site material pressing, rolling, and shaping operations, simplifying the manufacturing process and reducing the time required to create the abradable coating while maintaining ease of manufacture through standardized production methods.
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 process reduces manufacturing and maintenance times, lowers energy consumption, and enhances the aerodynamic properties of the abradable seals, enabling quicker and more reliable production with fewer defects and reduced downtime for aircraft engines.
Implementation Method 1
The material for forming the abradable track is generally in pasty form and is applied by an operator... The material is cured, for example by polymerisation at high temperature and under a controlled pressure.
Implementation Method 2
The mixture further comprises hollow glass spheres. The pieces thus have a low mass, reducing the energy consumption of the vehicle provided with such elements.
Data Source
AI summary
A molded piece 25 of abradable material for use in the manufacture of a segment of an abradable ring seal for a turbomachine includes a mixture of epoxy resin and crosslinking agent. The piece 25 has a curved shape and dimensions adapted to correspond to a receiver provided for that purpose in the inner surface of a casing of a fan of a turbomachine. A process for the manufacture of such a piece is also described.