Forward-Swept Outlet Guide Vanes for Shorter Turbofan Nacelles

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Solution Overview

Problem

Conventional turbofan engine designs with radially-oriented or aft-swept outlet guide vanes require an elongated outer nacelle, impacting aerodynamic performance and efficiency, while forward-swept OGVs pose acoustic challenges.

Innovation Solution

Incorporation of forward-swept outlet guide vanes with specific acoustic treatments on the outer casing of the turbomachine to address acoustic concerns and achieve a shorter turbofan engine design, enhancing aerodynamics 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 performance is maintained, but outer nacelle length increases impacting aerodynamic performance

Engineering Contradiction:

Improveacoustic performanceVSAvoidouter nacelle length

Core Design Contradiction:

Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The patent inverts the conventional OGV sweep direction from aft-swept or radially-oriented to forward-swept. This inversion allows the OGVs to be positioned closer to the fan, reducing outer nacelle length and improving aerodynamic performance while the acoustic treatments mitigate the associated acoustic challenges

Inventive Principle:

Principle #13The other way round (Inversion)

2Length of stationary object

If forward-swept outlet guide vanes are used, then outer nacelle length is reduced improving aerodynamics, but acoustic challenges arise

Engineering Contradiction:

Improveouter nacelle lengthVSAvoidacoustic performance

Core Design Contradiction:

Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces acoustic treatments as an intermediary element between the forward-swept OGVs and the surrounding environment. These treatments (such as acoustic liners or damping materials) mediate the acoustic challenges generated by the forward-swept configuration, allowing the beneficial aerodynamic compactness to be realized without compromising acoustic performance

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If outer nacelle length is reduced for aerodynamic efficiency, then aerodynamic performance improves, but acoustic compliance may be compromised

Engineering Contradiction:

Improveaerodynamic efficiencyVSAvoidacoustic compliance

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical parameters of the nacelle by reducing its length and implementing forward-swept OGVs to improve aerodynamic efficiency. Simultaneously, acoustic treatments are applied to modify the acoustic parameters, ensuring that the shortened configuration maintains acoustic compliance through controlled changes in acoustic properties

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12601311B2Gas turbine engine with forward swept outlet guide vanes

Publication Date: 2026.04.14 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.