Nacelle Concave Section for Gas Turbine Engine Aerodynamic Interaction

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Solution Overview

Problem

The close-coupled installation of gas turbine engines in aircraft leads to adverse aerodynamic interactions between the nacelle, wing, and pylon, limiting installation positions and increasing fuel burn and noise due to reduced space between the engine and wing.

Innovation Solution

Incorporating a concave section in the nacelle design that is curved radially inward near the trailing edge, increasing the gully distance between the nacelle and the wing, which reduces aerodynamic interactions and allows for larger engine sizes and more design options.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the gas turbine engine is installed in a close-coupled configuration closer to the wing, then mechanical integration with the aircraft is improved, but adverse aerodynamic interaction between the nacelle and wing increases

Engineering Contradiction:

Improvemechanical integrationVSAvoidaerodynamic interaction

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A concave section is incorporated into the outer surface of the nacelle, curved radially inwards relative to the outer surface. This curvature increases the gully distance between the nacelle and the wing, reducing adverse aerodynamic interactions while maintaining the close-coupled installation configuration for improved mechanical integration.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If the space between the gas turbine engine and the wing is reduced, then the installation position is more flexible, but aerodynamic interaction increases and limits viable installation positions

Engineering Contradiction:

Improveinstallation position flexibilityVSAvoidaerodynamic interaction

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The concave section with radial inward curvature creates additional clearance space between the nacelle and the wing. This allows the engine to be installed in close-coupled positions with greater flexibility while maintaining acceptable aerodynamic performance by reducing adverse interactions through the increased gully distance.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Object-affected harmful factors

If the gully distance between the nacelle and the wing is increased, then aerodynamic interaction is reduced, but the nacelle design becomes more complex

Engineering Contradiction:

Improveaerodynamic interactionVSAvoidnacelle design

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The concave section is defined by simple geometric parameters including a curvature radius R that is 0.05 to 0.15 times the nacelle diameter, and an azimuthal extent of 10 to 90 degrees. This curvature-based approach increases the gully distance to reduce aerodynamic interactions while maintaining a relatively simple and manufacturable nacelle design.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS11578617B2Nacelle for gas turbine engine and aircraft comprising the same

Publication Date: 2023.02.14 ROLLS ROYCE PLC

AI summary

A nacelle for a gas turbine engine includes a leading edge at an upstream side of the nacelle. The nacelle further includes a trailing edge at a downstream side of the nacelle. The nacelle further includes an outer surface disposed between the leading edge and the trailing edge. The nacelle further includes a concave section continuous with the outer surface and disposed proximal to the trailing edge. The concave section includes an upstream end and a downstream end spaced apart from the upstream end. The concave section is curved radially inwards relative to the outer surface between the upstream end and the downstream end.