Swirling Flow Combustor for Jet Engine Weight Reduction

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Solution Overview

Problem

Conventional thrust increasing devices require a long duct to ensure complete combustion, leading to increased engine weight and decreased thrust-to-weight ratio due to the need for a lengthy combustor to maintain fuel in the jet flow.

Innovation Solution

Incorporation of a swirling flow generating part with radial gutters that convert the jet flow into a swirling flow within the duct, enhancing mixing speed and allowing for a shorter combustion region by maintaining axial flow in the outer region and creating a swirling flow in the inner region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a long combustor is provided to ensure complete combustion reaction within the high-speed jet flow, then the combustion completeness is improved, but the duct length increases and the engine weight increases

Engineering Contradiction:
Improvecombustion completenessVSAvoidengine weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The invention changes the flow pattern parameter from axial flow to swirling flow by introducing a swirling flow generating part. This parameter change intensifies the mixing between fuel and oxidizer, accelerating the combustion reaction rate and allowing complete combustion to occur in a shorter residence time, thus reducing the required combustor length and engine weight while maintaining combustion completeness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The swirling flow creates a periodic recirculation pattern within the combustor where hot gases rotate and mix continuously with incoming fuel and air. This periodic motion enhances the combustion process by repeatedly bringing reactants into contact, ensuring complete combustion in a shorter distance compared to steady axial flow

Inventive Principle:
Principle #19Periodic action

2Productivity

If a long combustor is provided to maintain fuel in the jet flow for sufficient stay time, then the combustion efficiency is improved, but the duct length increases and the thrust-to-weight ratio decreases

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidengine weight
Core Design Contradiction:
ProductivityVSWeight of moving object

Solution Approach 1:

The invention changes the flow pattern parameter from axial flow to swirling flow by introducing a swirling flow generating part. This parameter change intensifies the mixing between fuel and oxidizer, accelerating the combustion reaction rate and allowing complete combustion to occur in a shorter residence time, thus reducing the required combustor length and engine weight while maintaining combustion completeness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces dynamic swirling motion to the previously static axial flow. The swirling flow creates dynamic mixing and recirculation patterns that enhance combustion efficiency by continuously renewing the contact between fuel and oxidizer, achieving high productivity in a compact configuration

Inventive Principle:
Principle #15Dynamics

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 enables faster fuel burning, reduces the duct length, and subsequently decreases the overall weight of the jet engine while maintaining thrust efficiency.

Implementation Method 1

a swirling flow generating part which maintains a flow of the jet flow in an axial direction of the duct in an outer region of the duct in a radial direction inside the duct and converts the jet flow to a swirling flow centered on an axis of the duct in an inner region of the duct in the radial direction inside the duct

Methodology Applied
Scientific EffectSwirling flow: Vortex Ring

Implementation Method 2

a fuel injector which ejects fuel toward a jet flow; an ignition device disposed downstream from the fuel injector

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3147489B1Thrust increasing device
Publication Date: 2020.11.04 IHI CORP
  • EP3147489B1 patent drawingFigure 1
  • EP3147489B1 patent drawingFigure 2
  • EP3147489B1 patent drawingFigure 3A~3B

AI summary

A thrust increasing device (10) includes: a fuel injector (10b) that ejects fuel toward a jet flow; an ignition device (10c) that is disposed downstream from the fuel injector; a cylindrical duct (10a) that surrounds a combustion region; a flame holder (10d) that is disposed in the duct; and a swirling flow generating part (10d) that maintains an axial (L) flow of the jet flow in an axial direction of the duct in an outer region of the duct in a radial direction inside the duct and that converts the jet flow to a swirling flow centered on an axis of the duct in an inner region of the duct in the radial direction inside the duct.