Jet Engine Combustor Igniter Disappearing Flame Holder

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Solution Overview

Problem

Conventional jet engine combustors require separate recesses for igniter installation and flame holding, leading to complex engine design, larger igniter sizes, and potential aerodynamic issues due to igniter cavity formation after activation.

Innovation Solution

A combustor design where the igniter is disposed in a flame holder that disappears after activation, creating a cavity that functions as a flame-holding space, eliminating the need for separate flame holder recesses and simplifying engine design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate recesses are provided for igniter installation and flame holding, then ignition and flame holding functions are achieved, but device complexity increases and igniter size increases

Engineering Contradiction:

Improveignition and flame holding functionVSAvoidengine design complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the igniter installation recess and flame holder recess into a single integrated recess structure. The igniter is installed in the same recess that serves as the flame holder, eliminating the need for separate recesses. This merging of functions reduces structural complexity while maintaining both ignition and flame holding capabilities through the unified recess geometry.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The recess structure is designed to serve multiple functions simultaneously: it acts as both the igniter installation cavity and the flame holder. This multi-functional design allows the same structural element to fulfill both ignition support and flame stabilization roles, thereby reducing the overall number of components and simplifying the engine combustor design.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate recesses are provided for igniter installation and flame holding, then ignition and flame holding functions are achieved, but igniter size increases

Engineering Contradiction:

Improveignition and flame holding functionVSAvoidigniter size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

By merging the igniter recess and flame holder recess into a single integrated structure, the igniter can be made more compact as it shares space with the flame holding function. The unified recess allows the igniter to be smaller since it doesn't require a separate dedicated cavity, thus reducing the overall igniter volume while maintaining functional reliability.

Inventive Principle:

Principle #5Merging (Combining)

3Power

If igniter is installed in deep recess for vigorous flame emission, then flame emission is improved, but aerodynamic performance deteriorates due to cavity formation after igniter activation

Engineering Contradiction:

Improveflame emission intensityVSAvoidaerodynamic performance

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The integration of igniter and flame holder recesses creates a unified cavity structure that is optimized to minimize aerodynamic disruption. By combining the functions, the recess geometry can be designed to reduce turbulence and flow separation after igniter activation, thereby maintaining better aerodynamic performance while still providing sufficient depth for vigorous flame emission.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If flame propagation from ignition to flame holding is required, then ignition process is completed, but ignition stability deteriorates

Engineering Contradiction:

Improveignition completionVSAvoidignition stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

By placing the igniter directly within the flame holder recess, the ignition source is positioned at the exact location where flame holding occurs. This eliminates the need for flame propagation across a distance, as the igniter flame directly establishes the combustion zone. The merged structure ensures that ignition and flame holding occur at the same spatial location, significantly improving ignition stability.

Inventive Principle:

Principle #5Merging (Combining)

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 design stabilizes ignition and flame keeping, reduces igniter size, and simplifies engine design by using the igniter's activation cavity as a flame-holding space, improving overall engine performance and aerodynamics.

Implementation Method 1

The igniter emits flame toward a space 150. The flame generated by the igniter ignites a gas mixture of a mainstream of air and the fuel

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

a method of forming a low speed region of the gas mixture using a shallow depression etc. formed in the wall surface of the combustor and keeping the flame using the low speed region

Methodology Applied

Scientific EffectFlow separation: Flow Separation

Data Source

PatentUS10697397B2Combustor, jet engine, flying body, and operation method of jet engine

Publication Date: 2020.06.30 MITSUBISHI HEAVY IND LTD

AI summary

A combustor of a jet engine includes a fuel injector, an igniter for igniting a gas mixture of air and fuel, and a flame holder. The igniter is disposed in the flame holder. After an activation of the igniter, the igniter disappears, and a space after the disappearance functions as a flame-holding space.