Movable Liner for Aero Engine Fan Blade Containment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fan blade containment systems in aero engines are inadequate for non-conventional fan blades, such as composite materials or wider tips, as they rely on penetration of a sacrificial liner, which may fail due to reduced pressure energy, and are prone to degradation over time, especially when dealing with ice shedding and varying blade designs.
Innovation Solution
A containment assembly with a movable liner element featuring a pivotally mounted wall portion that deflects and creates a containment cavity for detached fan blade fragments, eliminating the need for penetration and incorporating shock-absorbing materials and deflector portions to accommodate various blade types and ice impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sacrificial liner is used for fan blade containment, then conventional fan blades can be contained through penetration, but non-conventional fan blades (composite materials or wider tips) cannot be effectively contained due to reduced pressure energy
Solution Approach 1:
The liner is designed with a movable portion that can dynamically change its configuration. During normal operation, the movable portion maintains a sealed position. During an FBO event, the high-energy impact causes the movable portion to deflect and transition to an open configuration, allowing the blade fragment to penetrate and be contained. This dynamic behavior enables the system to adapt to different blade designs and energy levels.
Solution Approach 2:
The containment system changes its physical parameters based on the impact energy received. The movable portion of the liner transitions from a closed, sealed state during normal operation to an open, penetrated state during an FBO event. This parameter change allows the system to accommodate varying blade designs, materials, and tip widths that would otherwise be incompatible with fixed containment systems.
2Productivity
If the gap between blade tips and duct casing is minimized for efficiency, then air leakage is reduced, but rubbing between blade tips and casing occurs during certain operating conditions
Solution Approach 1:
A sacrificial abradable liner is installed on the inner surface of the duct casing before operation. This liner acts as a cushioning layer that is designed to be rubbed away by blade tips during normal operation. The liner material is softer than the blade tips, allowing it to erode preferentially and maintain smooth blade tip operation without damaging the blade tips or the structural casing.
3Weight of moving object
If Kevlar wrapping is used to reduce casing weight, then weight is reduced, but accessories bolted onto the fan case may contact the Kevlar wave during FBO events
Solution Approach 1:
The containment system is segmented into distinct functional zones. The Kevlar wrapping is confined to the containment structure where it needs to absorb impact energy, while accessories are positioned in separate zones that do not interact with the Kevlar deformation zone. This spatial segmentation allows the Kevlar to perform its weight-reduction function without compromising accessory attachment reliability.
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 provides reliable containment for diverse fan blade designs without degradation over time, ensuring effective engagement and retention of blade fragments and ice impacts, enhancing the containment system's reliability and adaptability.
Implementation Method 1
a fan blade fragment can enter the containment cavity when a detached fan blade fragment impacts on the moveable portion
Implementation Method 2
the moveable portion is deflectable from a sealed position in which it forms part of a continuous liner towards an open position
Implementation Method 3
the case is provided with a lining comprising a sacrificial abradable layer which is designed to be cut or rubbed away by the blade tips
Implementation Method 4
the Kevlar can absorb the blade energy by deflecting and stretching and thus diverting the load around the casing
Implementation Method 5
the Kevlar can absorb the blade energy by deflecting and stretching
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A containment assembly for a turbo fan engine, comprises a casing (30) arranged in use around a rotatable fan, to form a duct for the fan, the containment assembly comprising at least one liner element (32) disposed on an interior surface between the casing and blades (42) of a rotatable fan, the liner element comprising a body portion (34) mounted in a recess in the casing and a wall portion arranged to form part of an inner wall of the duct, the wall portion and the body portion being attached and defining a containment cavity (30a) therebetween for containment of a detached fan blade fragment in use, wherein the wall portion comprises a moveable portion (36) which is movable between a first configuration in which it lies substantially flush with the inner wall of the duct, and a second configuration in which it provides an opening through which a fan blade fragment can enter the containment cavity.