Embedded Visual Indicators in Gas Turbine Abradable Liners
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Solution Overview
Problem
The existing abradable liners in gas turbine engines suffer from in-service damage due to radial movement of fan blade tips caused by centrifugal forces, thermal expansion, and vibrations, leading to costly replacements during harsh operating conditions.
Innovation Solution
An abradable liner with embedded visual indicators, such as colored strips, is designed to monitor and control wear by being embedded within the abradable layers, allowing for partial replacement based on wear patterns, and providing clear visual cues for maintenance scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the abradable liner is initially installed in contact with fan blade tips to enable close fitting seal, then the leakage of compressed air is minimized, but the liner suffers in-service damage from radial movement of blade tips during harsh operating conditions
Solution Approach 1:
The patent applies preliminary action by pre-installing visual indicators (colored strips or dyed layers) within the abradable liner structure before the liner is installed in the engine. These indicators are positioned at specific depths and radial locations to predictively show wear patterns and potential failure zones before actual damage occurs, enabling proactive maintenance scheduling that prevents catastrophic liner failure during harsh operating conditions
2Manufacturing precision
If the abradable liner is designed to be scored by rotating fan blades during first few rotations to remove material for close fitting free rotation, then the blade tip clearance is optimized, but the liner requires expensive replacement when damaged
Solution Approach 1:
The patent implements self-service by enabling the liner to monitor and report its own wear condition through the visual indicators that become exposed as the liner wears during initial scoring and subsequent operation. This self-indicating capability allows maintenance personnel to assess liner condition and schedule replacements based on actual wear patterns rather than conservative time-based intervals, reducing unnecessary replacements and associated costs
3Adaptability or versatility
If the radial position of rotating blade tips moves due to centrifugal forces, thermal expansion and vibration during harsh operating conditions, then the engine can handle varied operating conditions, but the attrition liner suffers damage requiring replacement
Solution Approach 1:
The patent applies local quality by placing visual indicators at specific strategic locations within the liner structure - particularly at different radial depths and angular positions around the circumference. This localized placement allows different portions of the liner to indicate different wear mechanisms (radial wear, circumferential wear, localized erosion), providing detailed information about where and how the liner is being damaged by blade tip movements during varied operating conditions
Data Source
AI summary
An abradable liner suitable for a gas turbine engine fan stage, comprising a plurality of abradable layers that are bonded together, wherein at least one visual indicator is embedded in the plurality of abradable layers, the visual indicators can be coloured strips of material and may be at a given depth, and may be in an independent element or layer located in between other layers.