Segmented Fan Case Liner for Blade-Off Containment
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Solution Overview
Problem
Fan cases in gas turbine engines face challenges in maintaining dimensional tolerance and thermo-mechanical deflections, leading to the need for repair or replacement of liners, which can be costly and time-consuming, especially during blade-off events where rapid movement of liner segments is required to prevent blade ejection.
Innovation Solution
The design incorporates an annular outer shroud with coupled liner segments and a liner plate that allows for movement between the segments, enabling smooth transition and retention of fan blades during blade-off events, while allowing for independent replacement of liner segments for maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liners are permanently bonded to metallic shrouds using adhesives or hanger features, then dimensional tolerance between fan blades and fan case is maintained, but repair and replacement of liners becomes costly and time-consuming
Solution Approach 1:
The liner is divided into multiple removable liner segments that can be independently detached from the metallic shroud. Each segment can be separately removed and replaced without affecting the entire liner assembly or requiring permanent bonding, thus maintaining manufacturing precision while enabling easy repair.
Solution Approach 2:
The liner segments are designed to be dynamically removable and reconfigurable rather than permanently fixed. This allows the liner segments to be easily detached, replaced, or repositioned during maintenance operations while maintaining the required dimensional tolerance when installed.
2Strength
If liners are designed as single integrated pieces, then structural integrity is maintained, but replacement of entire liner assembly is required for minor damage
Solution Approach 1:
The liner is segmented into multiple independent sections that can be separately replaced. This allows only the damaged segment to be removed and replaced while the remaining segments stay in place, maintaining structural integrity of the overall liner assembly while significantly reducing replacement time.
Solution Approach 2:
Individual liner segments can be discarded when damaged and replaced with new segments, while the functional portions of the liner assembly are recovered and retained in service, avoiding the need to replace the entire liner assembly.
3Stability of the object's composition
If liner segments are rigidly fixed to the shroud, then positional stability is achieved, but rapid movement during blade-off events is restricted
Solution Approach 1:
The liner segments are designed with dynamic attachment features that allow them to move rapidly in response to blade-off events while maintaining positional stability during normal operation. The segments can detach or shift position when subjected to extreme forces from blade ejection.
Solution Approach 2:
The segmented design allows individual sections to move independently during blade-off events, enabling rapid local adjustment to contain blades while the overall liner assembly maintains its structural position within the fan case.
Data Source
AI summary
A fan case for use in a gas turbine engine of an aircraft includes an outer shroud and a liner extending along the outer shroud. The fan case provides a protective band that blocks fan blades from being thrown out of the fan case in case of a blade-off event in which a fan blade is released during operation of the gas turbine engine.