Structural Scroll Case for Aircraft Engine Load Support

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Solution Overview

Problem

Aerodynamic flow distributors in engine architectures, such as scroll or volute structures, are limited to their aerodynamic role and lack structural support, necessitating additional external components for engine stability and alignment.

Innovation Solution

A scroll case with a conduit having a non-axisymmetric portion that spirals towards the central axis and an axisymmetric portion extending downstream, which also serves as a structural component by supporting engine components and maintaining concentricity, eliminating the need for external structural cases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a scroll case is designed solely for aerodynamic flow distribution, then the aerodynamic performance is optimized, but structural support capability is insufficient, requiring additional external structural components

Engineering Contradiction:
Improveaerodynamic flow distributionVSAvoidstructural support capability
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The scroll case is designed to perform multiple functions simultaneously: it distributes aerodynamic flow to the turbine while also providing structural support for the turbine assembly and maintaining concentricity. This multi-functional design eliminates the need for separate external structural cases, reducing part count and overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The aerodynamic flow distribution function and structural support function are merged into a single integrated scroll case component. The case structure is designed to bear structural loads while maintaining its aerodynamic shape, combining what would traditionally be separate components into one unified structure.

Inventive Principle:
Principle #5Merging (Combining)

2Stability of the object's composition

If additional external structural cases are added to provide support, then structural stability is improved, but device complexity and part count increase

Engineering Contradiction:
Improveengine stabilityVSAvoidpart count
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The scroll case serves dual purposes as both an aerodynamic flow distributor and a structural support component. By making the scroll case structurally load-bearing, the design eliminates the need for separate external structural cases, thereby reducing part count while maintaining engine stability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The structural support function is merged into the scroll case itself rather than being provided by separate external components. This integration reduces the number of parts needed while ensuring the engine maintains its stability and alignment.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If the scroll case serves dual aerodynamic and structural functions, then part count and weight are reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvepart countVSAvoidconduit alignment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The scroll case incorporates a non-axisymmetric portion in its conduit design that transitions to an axisymmetric portion. This asymmetric design allows the case to maintain concentricity and alignment while serving both aerodynamic and structural functions, accommodating the increased manufacturing precision requirements through deliberate geometric design.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

Different portions of the scroll case have different geometric properties: a non-axisymmetric portion for aerodynamic flow distribution and an axisymmetric portion for structural support and alignment. This local variation in geometric quality allows the single component to meet both functional requirements with appropriate precision characteristics in each region.

Inventive Principle:
Principle #3Local quality

4Strength

If external structural cases are used, then structural support is provided, but radial envelope and compactness are increased

Engineering Contradiction:
Improvestructural supportVSAvoidradial envelope
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The structural support function is integrated into the scroll case itself, eliminating the need for external structural cases that would increase the radial envelope. The scroll case maintains structural integrity while occupying the same space required for aerodynamic flow distribution, thereby reducing the overall radial dimension of the engine assembly.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The scroll case performs both aerodynamic and structural functions within the same spatial envelope, eliminating the need for additional external components that would increase the radial size of the engine. This multi-functional design achieves structural support without compromising compactness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 scroll case effectively redirects combustion gases while providing structural support, reducing part counts, weight, and radial envelope, enhancing engine stability and compactness.

Implementation Method 1

a non-axisymmetric portion (22a) extending downstream from the inlet and spiraling towards the central axis

Methodology Applied
Scientific EffectSpiral flow: Vortex Ring

Data Source

PatentEP4446570A1Structural scroll case
Publication Date: 2024.10.16 PRATT & WHITNEY CANADA CORP
  • EP4446570A1 patent drawingFigure 1
  • EP4446570A1 patent drawingFigure 2
  • EP4446570A1 patent drawingFigure 3a~3b

AI summary

An aircraft engine (10) comprising a turbine (15), a scroll case (20) and an exhaust case (15B). A scroll case (20) is configured as a structural component to carry structural loads from other engine components, such as an internal containment ring (40), an exhaust casing (158) and an engine tailpipe.