Fan Case and Air Inlet Abradable Linings for Variable-Pitch Blades
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Solution Overview
Problem
Existing turbine engines with variable-pitch blades face issues of increased mass and size due to the need for a long-length abradable lining to accommodate varying contact zones, and conventional designs prevent easy dismounting of fan blades.
Innovation Solution
The fan case and nacelle air inlet are equipped with abradable linings on both structures, allowing the linings to be made of the same material and extending to different lengths, enabling the fan case to maintain a reduced length while accommodating variable-pitch blades, with the nacelle lining supporting the abradable material during specific pitch angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fan case is lengthened to accommodate a long-length abradable lining for variable-pitch blades, then the contact zone coverage is improved, but the mass and size of the turbine engine increase
Solution Approach 1:
The abradable lining is segmented into two separate components: a first peripheral lining mounted on the fan case and a second peripheral lining mounted on the air inlet. This segmentation allows each lining to be optimized independently in length and position, covering the variable contact zones of variable-pitch blades without requiring an excessively long fan case, thereby reducing overall engine mass while maintaining reliable contact coverage.
Solution Approach 2:
The air inlet acts as an intermediary structure that carries the second peripheral lining. By transferring part of the abradable lining function from the fan case to the air inlet, the fan case length can be reduced, decreasing engine mass while the second lining on the air inlet continues to provide necessary abradable contact coverage for variable-pitch blade operation.
2Reliability
If the fan case is lengthened to accommodate a long-length abradable lining, then the contact zone coverage is improved, but the dismounting of fan blades is prevented
Solution Approach 1:
By segmenting the abradable lining system into two separate linings on different components (fan case and air inlet), the air inlet with its second lining can be independently removed. This enables blade dismounting operations without requiring removal or modification of the entire fan case, maintaining ease of repair while ensuring continuous abradable coverage through the first lining on the fan case.
Solution Approach 2:
The second peripheral lining is extracted from the fan case structure and mounted on the air inlet instead. This extraction allows the air inlet assembly to be removed separately for blade maintenance, eliminating the constraint that a lengthened fan case would impose on blade dismounting, while the abradable function is preserved through the second lining on the removable air inlet.
3Reliability
If a single long abradable lining is used on the fan case, then the contact zone coverage is improved, but the structural complexity increases
Solution Approach 1:
The abradable lining function is segmented into two separate linings mounted on different components, which paradoxically simplifies the overall system. Each lining can be independently designed, installed, and maintained with optimal length for its specific location, avoiding the complexity of designing and managing a single extremely long lining that would need to accommodate all variable-pitch blade positions.
Solution Approach 2:
The air inlet structure is given a dual function: it serves both as the air intake component and as the mounting structure for the second peripheral lining. This multi-functionality eliminates the need for a separate long lining structure, reducing overall device complexity while maintaining comprehensive contact zone coverage through the coordinated first and second linings.
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 configuration optimizes air compression and reduces turbine engine mass and size, facilitates blade dismounting, and maintains structural integrity by distributing stress across multiple linings during different operational conditions.
Implementation Method 1
the abradable material configured to be capable of being worn out during the rotation of the fan
Implementation Method 2
a superficial layer of this abradable lining RAA detaches by friction when the blades 111 pass
Data Source
AI summary
An assembly for a turbine engine fan case and an air inlet, in particular for an aircraft. The turbine engine extending along a longitudinal axis and comprising at least one fan mounted so as to be rotatable about the longitudinal axis. The fan case comprising at least a first peripheral lining. The first peripheral lining being made of an abradable material configured to be capable of being worn out during the rotation of the fan. The air inlet comprising at least one second peripheral lining. The second peripheral lining being made of an abradable material configured to be capable of being worn out during the rotation of the fan.