Blade Tip Anodized Alumina Abrasive Layer
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Solution Overview
Problem
Existing blade tips in turbomachines, such as gas turbine engines, face damage during rub interactions due to inadequate protection, leading to increased clearance and potential wear, especially in high-temperature regions where conventional coatings fail to provide sufficient durability and abrasive properties.
Innovation Solution
A method of manufacturing blade tips with an anodized layer formed by roughening the surface to create protrusions, which are then converted to alumina, providing an abrasive surface that interfaces effectively with abradable rub coatings, thereby enhancing durability and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coatings are used on blade tips, then the blade tips are protected from damage during rub interactions, but the coatings fail to provide sufficient durability and abrasive properties in high-temperature regions
Solution Approach 1:
The patent changes the material parameter of the blade tip coating from conventional organic coatings to anodized alumina, which transforms the chemical composition and thermal properties. This parameter change enables the coating to withstand high temperatures while maintaining durability and abrasive properties, resolving the contradiction between coating reliability and temperature adaptability
Solution Approach 2:
The patent creates a composite structure by combining the metallic substrate with an anodized alumina layer. This composite material approach integrates the structural strength of metal with the high-temperature resistance and abrasive properties of ceramic alumina, achieving both durability and temperature resistance simultaneously
2Ease of manufacture
If the blade tip surface is made smooth, then the coating application is easier, but the blade tips lack sufficient abrasive properties to effectively interface with abradable rub coatings
Solution Approach 1:
The patent applies preliminary action by creating protrusions on the blade tip surface before the anodizing process. This pre-treatment ensures that the subsequent anodized layer forms an abrasive surface with the desired roughness and cutting ability, while still maintaining a controlled manufacturing process that begins with a smooth substrate
Solution Approach 2:
The patent transforms the surface parameter from smooth to rough through the anodizing process, which converts the metallic protrusions into ceramic alumina structures. This parameter change in surface roughness and material composition provides the necessary abrasive properties while the process remains manufacturable through standard anodizing techniques
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 anodized alumina surface on the blade tips improves durability and reduces wear ratio with abradable materials, allowing for tighter operating clearances and extended blade life across various engine stages without temperature limitations, while maintaining effective rub interaction and reduced blade temperature rise.
Implementation Method 1
anodizing to form the anodized layer so that the protrusions form an abrasive
Implementation Method 2
anodizing converting the entire tip surface to alumina
Data Source
Figure 1
Figure 2
Figure 2A
AI summary
A method is provided for manufacturing a blade. The blade (100) comprises an airfoil having: a root end and a tip (106); a metallic substrate (102) along at least a portion of the airfoil; and an anodized layer (154). The method comprises roughening the tip to form protrusions (158'; 402') and anodizing to form the anodized layer so that the protrusions form an abrasive (156; 400).