Fan Containment Case with Thermally Conforming Liner

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Gas turbine engines face challenges in effectively containing liberated fan blades, particularly due to shear threats and thermal expansion, which can lead to structural issues and reduced efficiency.

Innovation Solution

A fan containment case assembly with a ballistic liner made of resin-impregnated fibers, a thermally conforming liner assembly, and a honeycomb core, along with an abradable rub layer and torque blocks, is designed to surround and protect the fan blades, accommodating thermal expansion and providing structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ballistic liner is used to mitigate shear threats from liberated fan blades, then protection against blade shear is improved, but the containment case becomes more complex and heavier

Engineering Contradiction:

Improveprotection against blade shearVSAvoidcontainment case structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a composite ballistic liner construction combining aramid fibers for shear resistance with resin impregnation for structural integrity. This multi-material approach provides enhanced protection against liberated fan blades while managing the complexity through integrated material design rather than separate protective components

Inventive Principle:

Principle #40Composite materials

2Strength

If the containment case structure is made rigid to maintain structural integrity, then strength is improved, but thermal expansion and contraction are restricted causing stress

Engineering Contradiction:

Improvestructural integrityVSAvoidthermal expansion accommodation

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent modifies the structural parameters of the containment case by incorporating a wrap around the shell that permits controlled thermal expansion and contraction. This allows the structure to maintain strength while adapting to temperature variations during engine operation, preventing stress accumulation

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the shell is allowed to expand and contract with thermal changes, then thermal adaptability is improved, but structural stability deteriorates

Engineering Contradiction:

Improvethermal expansion accommodationVSAvoidstructural stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent uses a flexible wrap structure that can expand and contract with the shell during thermal cycles while maintaining structural stability. This flexible film approach allows thermal adaptability without compromising the overall structural integrity of the containment case

Inventive Principle:

Principle #30Flexible shells and thin films

4Loss of energy

If tip clearances are reduced to improve efficiency, then energy loss is reduced, but the risk of blade contact with the containment case increases

Engineering Contradiction:

Improveleakage lossesVSAvoidblade contact risk

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies different material properties and structural characteristics at different locations within the containment case. The ballistic liner provides localized protection where blade contact risk is highest, while other areas accommodate thermal expansion, enabling reduced tip clearances without increasing overall contact risk

Inventive Principle:

Principle #3Local quality

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 mitigates shear threats and thermal expansion, enhancing the structural integrity and efficiency of the fan containment case by allowing the shell and fan blades to expand and contract together, reducing tip clearances and leakage losses.

Implementation Method 1

ballistic liner made of resin-impregnated fibers

Methodology Applied

Scientific EffectFiber reinforcement:

Implementation Method 2

ballistic liner made of resin-impregnated fibers

Methodology Applied

Scientific EffectResin impregnation:

Implementation Method 3

accommodating thermal expansion and providing structural integrity

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

abradable rub layer

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3447306B1Fan containment case for gas turbine engine

Publication Date: 2020.07.22 RTX CORP

Figure 1
Figure 2
Figure 3

AI summary

The present invention relates to a fan containment case assembly (62) for a turbofan gas turbine engine, wherein the case assembly (62) includes an outer case (70) extending about an axis (A), and a thermally conforming liner assembly (78) radially inward of the outer case (70). The liner assembly (78) has a shell (82), a wrap (108) radially outward of the shell (82), and a ballistic liner (74) between the outer case (70) and the wrap (108). The wrap (108) has a first fiber construction, and the ballistic liner (74) has a second fiber construction that differs from the first fiber construction in stiffness. The wrap (108) is made of non-impregnated fibers, preferably aramid fibers, reducing overall weight. The ballistic liner (74) may be made of metal or of resin impregnated fibers. For mainting circumferential position of the liner assembly (78), ribs (114) cooperate with corresponding torque blocks (112).