Gas Turbine Nozzle Chevron Scalloped Root Drag Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing gas turbine engine nozzle designs with chevrons may increase drag, reducing engine efficiency and noise reduction effectiveness.

Innovation Solution

Incorporating scalloped root regions on the interior or exterior surfaces of chevrons in the nozzle to reduce drag and tailor airflow, enhancing engine efficiency and noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If chevrons are added to the nozzle to increase mixing and reduce noise, then noise reduction is improved, but drag increases and engine efficiency decreases

Engineering Contradiction:

ImprovenoiseVSAvoiddrag

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent applies local quality by scalloping only the root regions of specific chevrons rather than modifying the entire nozzle structure. This localized modification to the root geometry reduces drag in critical areas while preserving the noise-reducing chevron structures in other regions, thus addressing the contradiction between noise reduction and drag reduction.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If chevrons are added to the nozzle to increase mixing, then noise reduction is improved, but device complexity increases

Engineering Contradiction:

ImprovenoiseVSAvoidnozzle structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent modifies only the root regions of chevrons with scalloped geometries rather than redesigning the entire nozzle structure. This localized approach reduces complexity by maintaining the overall simple chevron design while adding minimal geometric complexity only where needed at the root regions to achieve the desired flow control.

Inventive Principle:

Principle #3Local quality

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 scalloped root regions decrease the drag coefficient of the nozzle, increasing engine efficiency and potentially improving fuel efficiency and noise reduction.

Implementation Method 1

The scalloped root regions decrease the drag coefficient of the nozzle, increasing engine efficiency

Methodology Applied

Scientific EffectDrag reduction through geometric modification: Drag

Implementation Method 2

the use of geometric structures known as chevrons may reduce low-frequency noise by increasing the rate at which the engine flow streams mix with the surrounding freestream air in the aft region of the nozzle

Methodology Applied

Scientific EffectTurbulent mixing: Turbulence

Data Source

PatentUS8356468B2Gas turbine engine nozzle configurations

Publication Date: 2013.01.22 THE BOEING CO

AI summary

In one embodiment, a gas turbine engine exhaust nozzle comprises a housing having a length which extends along a central longitudinal axis and comprising an interior surface and an exterior surface, and a row of chevrons extending from an aft end of the housing, the chevrons having a root region and a tip, wherein at least a portion of at least one of the interior surface or the exterior surface is scalloped proximate the root region of a chevron. Other embodiments may be described.