Forward-Swept Outlet Guide Vanes with Acoustic Treatment for Compact Turbofans

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Solution Overview

Problem

Conventional turbofan engine designs with radially-oriented or aft-swept outlet guide vanes result in elongated engines, impacting aerodynamic performance and efficiency, while forward-swept OGVs pose acoustic challenges that require specific acoustic treatments to maintain compliance.

Innovation Solution

Incorporation of forward-swept outlet guide vanes with integrated acoustic treatments on the outer casing of the turbomachine to address acoustic concerns and reduce engine length, combined with positioning the accessory gearbox inside the outer casing to maintain compactness and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If radially-oriented or aft-swept outlet guide vanes are used, then acoustic compliance is maintained, but engine length increases and aerodynamic performance deteriorates

Engineering Contradiction:

Improveacoustic complianceVSAvoidengine length

Core Design Contradiction:

Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The patent inverts the conventional orientation of outlet guide vanes from radially-oriented or aft-swept configurations to forward-swept configurations. This inversion allows the vanes to reduce engine length and improve aerodynamic performance while acoustic treatments are applied to maintain noise compliance, thus resolving the contradiction between engine compactness and acoustic requirements.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

Acoustic treatments are introduced as intermediary elements on the outer casing of the turbomachine. These treatments act as mediators that allow the forward-swept outlet guide vanes to operate without generating excessive noise, thereby enabling both compact engine design and acoustic compliance simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Length of moving object

If forward-swept outlet guide vanes are used, then engine length is reduced and aerodynamic performance is improved, but acoustic compliance deteriorates

Engineering Contradiction:

Improveengine lengthVSAvoidacoustic compliance

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

Acoustic treatments are applied to the outer casing as intermediary elements that mitigate the noise generated by forward-swept outlet guide vanes. This allows the vanes to maintain their beneficial aerodynamic properties while the acoustic treatments ensure noise levels remain compliant, resolving the contradiction between engine compactness and acoustic performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The acoustic treatment functionality is extracted as a separate component applied to the outer casing, distinct from the outlet guide vanes themselves. This separation allows the vanes to be optimized for aerodynamic performance and compactness while the acoustic treatments independently address noise compliance issues.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of repair

If accessory gearbox is positioned outside the outer casing, then maintenance access is improved, but device complexity and space requirements increase

Engineering Contradiction:

Improvemaintenance accessVSAvoidengine configuration

Core Design Contradiction:

Ease of repairVSDevice complexity

Solution Approach 1:

The accessory gearbox is nested within the outer casing of the turbomachine, similar to a nested doll configuration. This integration reduces overall engine complexity and space requirements while the gearbox remains accessible for maintenance through the redesign of access pathways, resolving the contradiction between compact integration and ease of repair.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent addresses maintenance access by changing the dimensional approach to accessibility - rather than positioning the gearbox externally for easy access, it is integrated within the casing structure with access provided through strategically located openings or removable panels, maintaining ease of repair within a compact three-dimensional configuration.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12385430B2Gas turbine engine with forward swept outlet guide vanes

Publication Date: 2025.08.12 GENERAL ELECTRIC CO

AI summary

A turbofan engine defining an axial direction and a longitudinal centerline along the axial direction is provided. The turbofan engine includes: a fan section having a fan, the fan comprising a plurality of fan blades; a turbomachine drivingly coupled to the fan, the turbomachine comprising a compressor section with a low pressure compressor, a turbine section with a low pressure turbine, a reduction gearbox, and an outer casing, the low pressure turbine drivingly coupled to the low pressure compressor across the reduction gearbox; an outer nacelle surrounding the fan and at least a portion of the turbomachine; an outlet guide vane extending between the turbomachine and the outer nacelle at a location downstream of the plurality of fan blades, the outlet guide vane defining a base and a tip and being forward swept from the base to the tip.