Aircraft Turbomachine Casing Abradable Layer Porosity Reduction
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Solution Overview
Problem
The existing fan casings in aircraft turbomachines face issues with porosity and low cohesion of the abradable material, leading to material loss and cracking, which affects the aerodynamic efficiency and reliability of the engine.
Innovation Solution
The introduction of fibrous reinforcements, such as glass, aramid, or carbon fibers, and a foam layer within the abradable material to enhance cohesion and reduce porosity, combined with a method of spreading the paste in sectors to minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick abradable layer is used to ensure minimum clearance between fan vanes and casing, then the aerodynamic efficiency is improved, but porosity and material loss increase due to low cohesion
Solution Approach 1:
The patent applies composite materials by incorporating fibrous reinforcements (glass, aramid, or carbon fibers) into the abradable material paste. This creates a composite structure that maintains the required thickness for aerodynamic clearance while significantly improving cohesion and reducing porosity. The fibers act as a reinforcing network that prevents material loss and cracking during operation.
2Strength
If fibrous reinforcements are added to the abradable material to improve cohesion, then manufacturing complexity increases, but manufacturing time decreases by 80%
Solution Approach 1:
The patent merges the reinforcement function directly into the abradable material paste formulation. The fibrous reinforcements are mixed into the paste before application, combining the structural reinforcement function with the abradable coating function in a single integrated material system. This eliminates the need for separate reinforcement installation steps, reducing manufacturing complexity despite the added material components.
3Ease of manufacture
If the abradable layer is applied in a conventional manner, then the coating process is simple, but porosities appear due to outgassing and deposition issues
Solution Approach 1:
The patent applies parameter changes by modifying the paste composition to include fibrous reinforcements and adjusting the spreading process parameters. The addition of fibers changes the rheological properties and outgassing behavior of the paste, while the sector-by-sector spreading method optimizes deposition conditions to minimize porosity formation during polymerization.
4Manufacturing precision
If the paste is spread in sectors to minimize defects, then the manufacturing process becomes more complex, but touch-up time decreases by 50%
Solution Approach 1:
The patent applies segmentation by dividing the abradable layer application into sequential sectors around the annular envelope. Each sector is prepared, spread, and allowed to polymerize independently before moving to the next sector. This segmented approach prevents defects from propagating across the entire structure and enables localized quality control, reducing the need for extensive touch-up work.
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 significantly reduces porosity and material loss, improves mechanical strength, and decreases manufacturing time by 80% and touch-up time by 50%, thereby enhancing the reliability and efficiency of the fan casing.
Implementation Method 1
an annular layer of abradable material extending inside the envelope, around the axis A, and obtained by spreading and polymerizing a paste
Data Source
AI summary
A casing of an aircraft turbomachine includes an annular shell extending around an axis A and made of a composite material having fibers that which are woven and embedded in a resin. An annular layer made of abradable material extends inside the shell, around axis A and is obtained by spreading and polymerizing a paste. Support panels extend around axis A and are interposed between the shell and the abradable layer.