Gas Turbine Seal Interlayer for Erosion Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Turboshaft engines operating in dusty environments face rapid erosion of abradable outer air seals, leading to increased tip clearance and reduced efficiency due to the harsh conditions, which existing abradable coatings fail to withstand effectively.
Innovation Solution
An abradable seal design featuring a substrate, an abradable layer, and an interlayer with abrasive particles that protrude out of the interface adjacent to the abradable layer, where the interlayer is harder than both the substrate and abradable layer, and contains metal matrix composite with hard particles like tungsten carbide and alumina or zirconia, which enhances erosion resistance and maintains tip clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an abradable outer air seal is used to reduce tip clearance and increase efficiency, then engine efficiency is improved, but the seal erodes rapidly in dusty environments leading to increased tip clearance
Solution Approach 1:
The seal is constructed as a composite structure with three distinct layers: a substrate layer, an interlayer containing abrasive particles, and an abradable layer. This composite design allows each layer to perform its specific function - the substrate provides structural support, the interlayer with abrasive particles (such as alumina or zirconia) provides erosion resistance, and the abradable layer maintains tip clearance control. The combination resolves the contradiction by integrating materials with complementary properties into a single functional component.
2Manufacturing precision
If the abradable layer is made softer to allow blade tips to rub and maintain clearance, then tip clearance control is improved, but the seal becomes more susceptible to erosion from abrasive particles
Solution Approach 1:
The interlayer containing abrasive particles serves as an intermediary between the soft abradable layer and the harsh dusty environment. This intermediate layer with its harder abrasive particles (alumina, zirconia, or carbides) protects the softer abradable layer from direct exposure to dust particles while still allowing the abradable layer to perform its clearance control function through controlled rubbing with blade tips.
3Reliability
If the seal material is made harder to resist erosion, then erosion resistance is improved, but the ability to maintain tight tip clearance through controlled wear is reduced
Solution Approach 1:
Different regions of the seal have different material properties optimized for their specific functions. The substrate layer has high hardness for structural support and erosion resistance, the interlayer contains concentrated abrasive particles for enhanced erosion protection, and the abradable layer has lower hardness to enable controlled wear for tip clearance maintenance. This spatial variation in material quality resolves the contradiction by applying hardness where needed for protection and softness where needed for clearance control.
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 solution effectively limits tip clearance erosion, maintains engine efficiency, and allows for repair by preventing erosion from reaching the substrate, thus improving stability and power capability while reducing material wear.
Implementation Method 1
the interlayer containing abrasive particles of which at least some abrasive particles protrude out of an interface adjacent to the abradable layer
Data Source
AI summary
A seal for a gas turbine engine including an interlayer between a substrate and an abradable layer, the interlayer containing abrasive particles of which at least some abrasive particles protrude out of an interface that abuts the abradable layer.