Fan Case Abradable Liner Drainage Trenches

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Solution Overview

Problem

Water pooling and freezing inside the fan case of a gas turbine engine can prevent the fan from rotating, causing startup issues and potential engine damage, and existing drainage solutions compromise the structural integrity and increase weight and cost.

Innovation Solution

A drainage system featuring radial slots and trenches within the abradable liner of the fan case allows water to escape without compromising structural integrity, using a design that includes radial slots on the mating surface and corresponding passages and trenches within the liner to facilitate free drainage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If simple drainage holes are drilled through the fan case, then water drainage function is improved, but structural integrity deteriorates and weight increases due to required reinforcement

Engineering Contradiction:

Improvewater drainage functionVSAvoidstructural integrity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The drainage function is extracted from the fan case structure by using the abradable liner as the drainage medium. The liner material itself provides the drainage capability through its porous structure, eliminating the need for structural modifications to the fan case for drainage purposes.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The abradable liner is positioned specifically at the drainage location to provide localized drainage functionality. This allows the fan case structure to remain intact and strong while the liner material at the specific drainage location provides the necessary water escape paths through its porous nature.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If drainage holes are drilled through the fan case, then water drainage function is improved, but manufacturing cost increases due to reinforcement requirements

Engineering Contradiction:

Improvewater drainage functionVSAvoidmanufacturing cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The drainage function is extracted from the fan case structure and assigned to the abradable liner material. This eliminates the need for expensive structural reinforcement and complex drilling operations on the fan case, reducing manufacturing costs while maintaining drainage functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The abradable liner is a consumable component that can be easily replaced. Using this disposable-like component for drainage functionality is more economical than permanently modifying the expensive fan case structure with reinforcement and drilled holes.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Strength

If the fan case structure is reinforced to maintain integrity with drainage holes, then structural integrity is improved, but weight increases significantly

Engineering Contradiction:

Improvestructural integrityVSAvoidfan case weight

Core Design Contradiction:

StrengthVSWeight of stationary object

Solution Approach 1:

The drainage function is taken out from the structural component (fan case) and assigned to the non-structural component (abradable liner). This eliminates the need for structural reinforcement that would increase weight, as the liner material provides drainage without requiring additional structural support.

Inventive Principle:

Principle #2Taking out (Extraction)

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

Prevents water pooling and freezing without increasing the weight or cost of the fan case, maintaining structural integrity and allowing for easy manufacturing and repair, while ensuring proper drainage for different installation attitudes.

Implementation Method 1

Since the abradable liner of the fan case has a relatively rough and porous surface

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a drainage system allowing water to freely escape the fan case

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS8613591B2Fan case abradable drainage trench and slot

Publication Date: 2013.12.24 PRATT & WHITNEY CANADA CORP

AI summary

A fan case for a gas turbine engine is provided to prevent water from pooling and freezing inside the fan case when the gas turbine is not in operation, and potentially prevent the engine from starting and/or cause engine damage. The fan case is therefore adapted to provide a drainage system allowing water to freely escape the fan case without compromising the structural integrity of the fan case. The fan case comprises: a hollow body; an abradable liner disposed inside the hollow body; a flange on the hollow body defining a surface for mating to a forward part of the engine; and, a first radial slot extending across the mating surface of the hollow body. The abradable liner has an inside surface for circumscribing the fan blades wherein the first radial slot is in a free-draining relation with the inside surface of the abradable liner.