Abrasive Cutting Edge Integrally Bladed Rotor Seal Management
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Solution Overview
Problem
Conventional abradable air seal systems in gas turbine engines face challenges in balancing efficiency, maintenance costs, and erosion resistance, often requiring abrasive tip coatings like CBN that increase costs and complexity.
Innovation Solution
The design features a blade with a chamfered tip surface and a cutting edge that includes abrasive particles in a matrix material, allowing for efficient abrading of the seal without the need for CBN, combined with a method of machining or forging the cutting edge and coating with materials like TiN, TiCN, or diamond for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abradable material density and hardness are increased to improve erosion resistance, then erosion resistance is improved, but the difficulty of abrading the seal increases
Solution Approach 1:
The blade tip surface incorporates a cutting edge with abrasive particles (such as CBN, diamond, or carbide) concentrated at the cutting edge region, while the rest of the blade maintains standard material properties. This localized application of abrasive material allows the blade to effectively abrade dense abradable seals without requiring the entire blade to be made of expensive abrasive materials, thus resolving the contradiction between erosion resistance and abradability.
Solution Approach 2:
The blade tip employs a composite structure combining a base material with an abrasive particle coating or infiltration layer. The cutting edge contains abrasive particles embedded in a matrix material, creating a composite that provides both the hardness needed for erosion resistance and the abrasiveness required for effective seal cutting. This composite approach allows simultaneous achievement of erosion resistance and abradability.
2Ease of manufacture
If abrasive tip coatings such as CBN are applied to blades to enable effective abrading of dense seals, then abradability is improved, but blade cost increases
Solution Approach 1:
Abrasive particles are applied only to the cutting edge region of the blade tip where they are most needed for abradability, rather than coating the entire blade. This localized treatment significantly reduces material costs while maintaining effective abrading capability where required. The cutting edge may have a concentration of abrasive particles that decreases toward the blade body, optimizing cost-effectiveness.
Solution Approach 2:
The blade tip design allows the abrasive cutting edge to wear down during operation, with the understanding that this wear is part of the normal function. The blade can be designed with a replaceable or regenerable cutting edge, or the entire blade can be economically replaced when the abrasive layer is depleted, avoiding the need for expensive maintenance of the abrasive coating throughout the blade's service life.
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 reduces friction and heat generation, enhances blade life, and improves engine efficiency, particularly in high-pressure compressor sections, while reducing costs by eliminating the need for CBN tipping and maintaining effective abrading capabilities.
Implementation Method 1
the cutting edge is configured to abrade a seal section of an engine case
Implementation Method 2
reduces friction and heat generation
Implementation Method 3
reduces friction and heat generation, enhances blade life
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An integrally bladed rotor,(111) including: a plurality of blades (114; 214; 314; 414) integrally formed with a hub (112) as a single component, each of the plurality of blades (114; 214; 314; 414) having a blade body (124; 324; 424) extending from the hub (112) to an opposed blade tip surface (128; 228; 328; 428) along a longitudinal axis, wherein the blade body (124; 324; 424) defines a pressure side (130; 230; 330; 430) and a suction side (132; 232; 332; 432), and wherein the blade body (124; 324; 424) includes a cutting edge (134; 234; 334; 434) defined between the blade tip surface (128; 228; 328; 428) of the blade body (124; 324; 424) and the pressure side (130; 230; 330; 430) of the blade body (124; 324; 424), wherein the cutting edge (134; 234; 334; 434) is configured to abrade a seal section (116) of an engine case (110). A method for manufacturing an integrally bladed rotor (111) includes: forming a plurality of airfoils integrally with a hub (112) to form a single component, each of the plurality of airfoils having an opposed tip surface (128; 228; 328; 428) with respect to the hub (112) extending along a longitudinal axis, wherein each of the plurality of airfoils defines a pressure side (130; 230; 330; 430) and a suction side (132; 232; 332; 432); and forming a cutting edge (134; 234; 334; 434) between the tip surface (128; 228; 328; 428) and the pressure side (130; 230; 330; 430) of each of the plurality of airfoils, wherein the cutting edge (134; 234; 334; 434) is configured to abrade a seal section (116) of an engine case (110).