Aircraft Engine Inlet Shoulder for Boundary Layer Deflection

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Solution Overview

Problem

Existing aircraft designs struggle to efficiently deflect the boundary layer flow away from the inlet opening of jet engines, resulting in lower energy air intake and reduced engine performance.

Innovation Solution

The aircraft structure incorporates a compression surface, transition shoulder, and a flow guide surface as local elevations to deflect the boundary layer fluid away from the inlet opening, enhancing the displacement of low-energy air flow and improving the energy of the air intake.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If elevations (or bumps) are arranged on the outer surface of the aircraft to deflect the boundary layer away from the inlet opening, then the energy of the air flow received into the inlet opening is improved, but the complexity of the aircraft structure increases

Engineering Contradiction:

Improveenergy of air flowVSAvoidcomplexity of aircraft structure

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating a flow guide surface with a specific curvature profile only in the critical region where the boundary layer interacts with the inlet opening. This localized modification deflects the boundary layer away from the inlet while maintaining the simplicity of the rest of the aircraft structure, thus improving air flow energy without unnecessarily increasing overall structural complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes curvature by designing the flow guide surface with a specific curvature profile that smoothly deflects the boundary layer. The curved geometry of the flow guide surface allows for a gradual redirection of flow, reducing flow separation and turbulence while effectively moving the boundary layer away from the inlet opening, thereby improving energy content of the incoming air.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Productivity

If the inlet opening size is reduced to improve aircraft performance, then the displacement of boundary layer fluid is improved, but the amount of air available for the engine decreases

Engineering Contradiction:

Improvedisplacement of boundary layer fluidVSAvoidamount of air

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent applies parameter changes by modifying the curvature profile of the flow guide surface to optimize the displacement effect. By carefully selecting the curvature parameters of the flow guide surface, the design achieves effective boundary layer displacement with minimal impact on the total air quantity entering the inlet, thus improving productivity while maintaining adequate air supply.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the curvature profile of the flow guide surface is optimized to improve boundary layer displacement, then the efficiency of air flow energy transfer is improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveefficiency of air flow energy transferVSAvoidprecision of curvature profile

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent uses curvature in a controlled and practical manner by designing the flow guide surface with a specific curvature profile that can be manufactured using conventional techniques. The curvature is applied in a way that balances flow optimization with manufacturing feasibility, avoiding excessively complex geometries while still achieving effective boundary layer displacement and improved energy transfer efficiency.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

This configuration allows for a more efficient air intake into the jet engine, increasing its performance by ensuring higher energy air flow, and potentially reducing the size of the inlet opening.

Implementation Method 1

the boundary layer of the flow, which is generated on the outer skin of the aircraft, is deflected away from the inlet opening

Methodology Applied

Scientific EffectBoundary layer: Boundary Layer

Implementation Method 2

The flow guide surface, in a cross-sectional view (z-y plane) of the aircraft structure, is distinguished by a width and a height relative to the transition shoulder

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

The first contour line on the flow guide surface is distinguished by a change in the curvature profile

Methodology Applied

Scientific EffectFlow separation: Flow Separation

Data Source

PatentUS12630287B2Aircraft structure having an improved inlet opening for engine air

Publication Date: 2026.05.19 AIRBUS DEFENCE & SPACE GMBH

AI summary

An aircraft structure having a fuselage, an engine and an air inlet for receiving air for the engine. The air inlet has a cowl which surrounds an inlet opening. The air inlet has a compression surface and a transition shoulder. The air inlet additionally has a flow guide surface, which is arranged as a local elevation in a region of the transition shoulder and extends into the inlet opening. This flow guide surface designed as a local elevation contributes to improving the displacement of the boundary layer of a fluid flowing along the aircraft structure at the air inlet.