Induction Plasma Torch Tapered Wall for Energy Density
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Solution Overview
Problem
Induction plasma torches face limitations in achieving higher plasma energy density due to maximum temperature constraints of the plasma confinement tube material and suffer from stray-arcing issues between the plasma gas discharge and reactor components.
Innovation Solution
The design incorporates a plasma confinement tube with a tapered wall thickness, which reduces heat flux distribution, and an annular cooling channel with a constant thickness for efficient cooling, along with a capacitive shield to minimize capacitive energy coupling and stray-arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the energy density in the plasma is increased, then the bulk specific enthalpy and average temperature of the plasma are improved, but the heat flux to the inner surface of the plasma confinement tube increases causing tube failure
Solution Approach 1:
The plasma confinement tube employs varying wall thickness along its axial length, with the thickest section positioned at the location of maximum heat flux. This non-uniform thickness distribution optimizes local heat dissipation capacity where it is most needed, allowing the tube to withstand higher plasma energy densities without failure.
Solution Approach 2:
The invention introduces a new design dimension by transitioning from uniform to variable wall thickness along the axial direction of the tube. This dimensional variation in the thickness parameter enables differentiated thermal management at different axial positions, resolving the contradiction between energy density and tube reliability.
2Power
If high frequency electrical current is supplied to the induction coil, then plasma ignition and heating are achieved, but stray-arcing occurs between the plasma gas discharge and reactor components
Solution Approach 1:
The invention introduces a capacitive shield as an intermediary component positioned between the plasma discharge and reactor components. This shield acts as a mediator that blocks capacitive energy coupling pathways, preventing stray-arcing while allowing the induction coil to deliver full heating power to the plasma.
3Temperature
If the plasma confinement tube is made of high-temperature-resistant ceramic material, then the tube can withstand higher temperatures, but the maximum energy density is still limited by the material's temperature tolerance
Solution Approach 1:
The varying wall thickness design concentrates the thickest section at the location of maximum heat flux, enabling the tube to withstand higher local temperatures without exceeding material tolerance. This allows higher overall plasma energy density to be achieved while maintaining tube integrity through optimized local thermal management.
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 allows for increased plasma energy density while maintaining the structural integrity of the plasma confinement tube and significantly reducing stray-arcing, with improved cooling efficiency and reduced risk of tube failure.
Implementation Method 1
the high frequency electrical current flowing though the induction coil 104 creates within the plasma confinement tube 102 a generally axial high frequency magnetic field 120. The energy of this magnetic field 120 causes electrical breakdown of the plasma gas 108 present in the plasma confinement tube 102. Once electrical breakdown and plasma ignition is achieved, a tangential current is induced into the plasma gas in a region 122 within the plasma confinement tube 102 at the level where the induction coil 104 is located. This induced, tangential current is responsible for heating the plasma gas 108 in the plasma confinement tube 102 and sustaining the plasma gas discharge forming the plasma 110.
Implementation Method 2
the thickness of the tubular wall 220 of the plasma confinement tube 218 is in inverse proportion to the distribution of heat flux on the tubular wall 220 of the plasma confinement tube 218. An annular channel 224 is defined between an outer surface of the tubular wall 220 of the plasma confinement tube 218 and an inner surface of the torch body 204 for receiving a cooling fluid to cool the plasma confinement tube 218.
Data Source
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AI summary
An induction plasma torch comprises a tubular torch body, a tubular insert, a plasma confinement tube and an annular channel. The tubular torch body has upstream and downstream sections defining respective inner surfaces. The tubular insert is mounted to the inner surface of the downstream section of the tubular torch body. The plasma confinement tube is disposed in the tubular torch body, coaxial therewith. The plasma confinement tube has a tubular wall having a thickness tapering off in an axial direction of plasma flow. The annular channel is defined between, on one hand, the inner surface of the upstream section of the tubular torch body and an inner surface of the insert and, on the other hand, an outer surface of the tubular wall of the plasma confinement tube. The cooling channel carries a fluid for cooling the plasma confinement tube.