Microwave Plasma Flame Generation with Swirl-Gas Wall Cooling

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Solution Overview

Problem

Existing plasma generation methods are limited by uneven thermal distribution and excessive heating of the plasma combustion chamber wall, leading to potential damage and reduced operational efficiency.

Innovation Solution

The plasma combustion chamber wall is secured outside the cavity resonator and at a distance, with coolant channels to manage temperature gradients, and multiple cooling sections and swirl gas jackets to distribute heat uniformly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the plasma combustion chamber wall is made of dielectric material to separate plasma from cavity resonator, then plasma containment and microwave transparency are improved, but excessive heat transfer to the wall causes damage and limits maximum heat output

Engineering Contradiction:
Improveplasma containmentVSAvoidplasma combustion chamber wall temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

A swirl gas jacket is introduced as an intermediary substance between the plasma flame and the dielectric combustion chamber wall. This gas layer acts as a thermal barrier, absorbing and carrying heat away from the wall surface while allowing the plasma to maintain its high temperature for processing. The swirl gas flows in a manner that creates a protective cushion between the hot plasma and the wall, preventing direct thermal contact and subsequent wall damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the plasma combustion chamber wall is positioned inside the cavity resonator for efficient microwave coupling, then energy efficiency is improved, but uneven thermal distribution causes localized overheating and wall damage

Engineering Contradiction:
Improvemicrowave energy coupling efficiencyVSAvoidthermal distribution uniformity
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The solution introduces a third dimension of heat management by implementing a three-dimensional swirl gas flow pattern around the plasma flame. Instead of relying solely on radial heat distribution, the tangential swirl component creates axial and radial temperature gradients that distribute heat more uniformly across the combustion chamber wall surface. This multi-dimensional flow pattern prevents localized hot spots while maintaining efficient microwave coupling.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If the plasma flame is directed perpendicular to microwave propagation for optimal plasma generation, then plasma production efficiency is improved, but heat concentration on specific wall areas causes localized thermal stress and damage

Engineering Contradiction:
Improveplasma generation efficiencyVSAvoidthermal stress on plasma combustion chamber wall
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The swirl gas flow introduces dynamic parameter changes to the thermal field by creating time-varying temperature distributions on the wall surface. The rotating swirl pattern continuously redistributes thermal load across different wall areas, preventing sustained concentrated heating at any single location. This temporal and spatial parameter variation allows the plasma to operate at high efficiency while the wall experiences distributed, manageable thermal stress.

Inventive Principle:
Principle #35Parameter changes

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 allows for a higher and more uniform heat output of the plasma flame, preventing damage to the plasma combustion chamber wall and enabling continuous operation with enhanced thermal management.

Implementation Method 1

microwave energy is supplied to the cavity resonator via a waveguide in order to generate a plasma in the plasma combustion chamber

Methodology Applied
Scientific EffectMicrowave energy: Microwave Radiation

Implementation Method 2

microwave energy is supplied to the cavity resonator via a waveguide in order to generate a plasma

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

the plasma combustion chamber wall is secured outside the cavity resonator and at a distance, with coolant channels to manage temperature gradients

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

coolant channels to manage temperature gradients, and multiple cooling sections and swirl gas jackets to distribute heat uniformly

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 5

a swirl gas is blown into the plasma combustion chamber with a swirl generating device in order to generate a swirl gas jacket surrounding the plasma flame

Methodology Applied
Scientific EffectVortex flow: Vortex Ring

Implementation Method 6

a swirl gas is blown into the plasma combustion chamber with a swirl generating device in order to generate a swirl gas jacket surrounding the plasma flame

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4385290B1Method for generating a plasma flame and plasma-generating device
Publication Date: 2025.08.20 MUEGGE
  • EP4385290B1 patent drawingFigure 1
  • EP4385290B1 patent drawingFigure 2~3

AI summary

In a method and a plasma-generating device (1) for generating a plasma flame (21) with a plasma combustion gas which is blown in a plasma flame direction (8) out of a plasma combustion chamber (2) through a plasma flame opening (6), the plasma combustion chamber (2) is at least partially arranged in a cavity resonator (4) to which microwave energy is supplied in order to generate plasma in the plasma combustion chamber (2). A swirling gas is blown into the plasma combustion chamber (2) by means of a swirl-generating device (9) in order in the plasma combustion chamber (2) to generate a swirling gas shell which surrounds the plasma flame (21) and shields a plasma combustion chamber wall (3) composed of a dielectric solid material in relation to the plasma flame (21). The plasma combustion chamber wall (3) protrudes along the plasma flame direction (8) beyond the cavity resonator (4) in both directions and is in each case fixed in a plasma combustion chamber wall holder (10) at a distance from the cavity resonator (4), wherein the plasma combustion chamber wall holder (10) has at least one holder cooling cavity (11) through which a coolant flows.