Anisotropic Honeycomb Liner Panel for Gas Turbine Fan Casing
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Solution Overview
Problem
Conventional fan tracks in gas turbine engines are not strong enough to handle ice impacts from swept fan blades, which can disrupt the blade trajectory and compromise the containment system during a blade-off event, as they are designed to be weak to allow debris passage.
Innovation Solution
A liner panel comprising an aluminium honeycomb with skewed cell walls and an abradable liner is positioned radially outward of the fan blades, providing sufficient strength to absorb ice impact energy while maintaining the integrity of the containment system by not interfering with the trajectory of released blades or fragments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fan track is made weak to allow debris passage during blade-off events, then the containment system can operate correctly, but the fan track cannot tolerate ice impact from swept fan blades
Solution Approach 1:
The liner panel is segmented into distinct functional zones: an abradable liner portion for the fan track that allows debris passage, and a honeycomb reinforcement portion that provides ice impact strength. This segmentation allows each zone to perform its specific function without compromising the other.
Solution Approach 2:
Different portions of the liner panel have different mechanical properties tailored to their specific functions. The abradable liner portion is soft and compliant to allow blade debris passage, while the honeycomb reinforcement portion is strong and rigid to absorb ice impact energy.
2Strength
If the fan track is strengthened to accommodate ice impact, then ice impact tolerance is improved, but the blade trajectory during blade-off events is disrupted and containment system operation is compromised
Solution Approach 1:
The liner panel divides the reinforcement function from the abradable function, placing honeycomb structure only in regions where ice impact protection is needed while maintaining abradable material in the fan track region where debris passage is critical.
Solution Approach 2:
The liner panel combines two different materials with complementary properties: an abradable liner material (such as phenolic resin or rubber) that is soft and compliant, and a honeycomb reinforcement material (such as aluminium or plastic honeycomb) that is strong and rigid. This composite structure achieves both ice impact tolerance and debris passage capability.
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 deflects ice impacts back into the gas stream while allowing released blades or fragments to pass through unimpeded, ensuring the containment system operates correctly and preventing damage from ice impacts.
Implementation Method 1
providing sufficient strength to absorb ice impact energy
Implementation Method 2
The cell walls of the honeycomb are at an angle to the radial direction of the engine, such that the honeycomb is stronger in a direction parallel to an expected trajectory of ice released from the blades than in a radial direction
Implementation Method 3
the fan blades cut a path into this abradable layer
Implementation Method 4
the fan blades cut a path into this abradable layer, minimising leakage around the blade tips
Implementation Method 5
The cell walls of the honeycomb are at an angle to the radial direction of the engine, such that the honeycomb is stronger in a direction parallel to an expected trajectory of ice released from the blades than in a radial direction
Data Source
AI summary
A liner panel for a fan casing of a gas turbine engine includes a honeycomb layer, a septum layer and an abradable layer. The fan casing is provided with a containment system in case of fan blade failure. In use, ice may be released from a fan blade in a first direction, and (in the case of a blade-off event) a fan blade or part of a fan blade may be released in a second direction. The panel has a compressive strength greater in the first direction than in the second direction such that the released ice will be deflected by the panel but the released fan blade or part of a fan blade will pass through the panel.