RF Plasma Flow Research Articles

Study of RF plasma flow at low pressure: electron temperature influence

A mathematical model of low-pressure RF plasma flow taking into consideration electron temperature influence is presented. Results of calculations of carrier gas velocity, pressure and temperature as well as electron density and electron temperature in plasma flow are showed. Influence of electric field on electron temperature and plasma flow is analyzed.

Experimental installation to study the RF plasma flow at low pressures with experiment data synchronization

A diagram and description of an experimental setup for studying the properties of a stream of RF plasma at low pressure are presented. The setup is equipped with diagnostic devices that record the temperature, volt-ampere characteristics, and pressure in the chamber.

Mathematical modelling of RF plasma flow at low pressure with metastable and electrodynamics

A mathematical model of the RF plasma flow at 0.15–150 Pa, Knudsen 0.03≤Kn≤3 with metastable atoms and electrodynamics is described. The model based on both astatistical approach for the neutral component of the RF plasma and the continuum model for electron, ion components, metastable and electric field. The results of plasma flow calculations for an undisturbed jet are described.

Mathematical Modelling of RF Plasma Flow at Low Pressures with 3D Electromagnetic Field

In this study, a hybrid mathematical model of a low-pressure RF plasma jet in transition mode between continuum and free molecular flow at a Knudsen number of 8·10−3 ≤ Kn ≤ 7·10−2 for a carrying gas is described. The model takes electrons, ions, metastable atoms, and potential and curl electromagnetic fields into account. The model is based on both a statistical approach for the atoms in the ground state and a continuum model for other components. The results of plasma flow calculations in an undisturbed jet are described. The distributions of the electrodynamic and electrostatic parts of the electric field are given. It has been observed that the plasma jet has a layered structure along the stream: a positive charge region is formed at the beginning of the jet, followed by a negative charge region, and then a positive one again. The reason for the formation of a layered structure is the fast flow expansion when the plasma inflows into the vacuum and the difference in electron and ion pulse.

Mathematical modelling of RF plasma flow at low pressure with electrodynamics

The mathematical model of the RF plasma at low pressure in both free-molecule and transition flow at Knudsen 0.03 ≤ Kn ≤ 3 is described. The model is based on the statistical approach for the neutral component of the plasma together with the continuum model for electron, electromagnetic field and metastable components. Results of plasma flow parameters calculations and testing results of electric field calculations are presented.

Simulation of rarefied low pressure RF plasma flow around the sample

The paper describes a mathematical model of the flow of radio frequency plasma at low pressure. The hybrid mathematical model includes the Boltzmann equation for the neutral component of the RF plasma, the continuity and the thermal equations for the charged component. Initial and boundary conditions for the corresponding equations are described. The electron temperature in the calculations is 1-4 eV, atoms temperature in the plasma clot is (3-4) • 103 K, in the plasma jet is (3.2-10) • 102 K, the degree of ionization is 10-7-10-5, electron density is 1015-1019 m-3. For calculations plasma parameters is developed soft package on C++ program language, that uses the OpenFOAM library package. Simulations for the vacuum chamber in the presence of a sample and the free jet flow were carried out.

Numerical and experimental study of a warming up effect of an underexpanded rarefied rf plasma jet outflowing into a flooded area

A mathematical model of the rf plasma flow at 13.3-133 Pa in transition regime at Knudsen number values 8 × 10-3 ≤ Kn ≤ 7 × 10-2 and the nozzle pressure ratio n = 10 for the carrier gas is described. The model based on both the statistical approach to the neutral component of the rf plasma and the approach to the continuum model for electron and ion components. The results of plasma flow calculations performed both for an undisturbed flow and for the stream with a sample at a prescribed electric field are described. The effect of a warming up of a stream in a mixture zone confirmed by comparison of numerical results with experimental ones is found.

Advancement of In-Flight Alumina Powder Spheroidization Process with Water Droplet Injection Using a Small Power DC-RF Hybrid Plasma Flow System

The correlation between plasma thermofluid characteristics and alumina powder spheroidization processes with water droplet injection using a small power DC-RF hybrid plasma flow system was experimentally clarified. Micro-sized water droplets with a low water flow rate were injected into the tail of thermal plasma flow so as not to disturb the plasma flow directly. Injected water droplets were vaporized in the thermal plasma flow and were transported upstream in the plasma flow to the torch by the backflow. After dissociation of water, the production of hydrogen was detected by the optical emission spectroscopy in the downstream RF plasma flow. The emission area of the DC plasma jet expanded and elongated in the vicinity of the RF coils. Additionally, the emission area of RF plasma flow enlarged and was visible as red emission in the downstream RF plasma flow in the vicinity below the RF coils due to hydrogen production. Therefore, the plasma flow mixed with produced hydrogen increased the plasma enthalpy and the highest spheroidization rate of 97% was obtained at a water flow rate of 15 Sml/min and an atomizing gas flow rate of 8 Sl/min using a small power DC-RF hybrid plasma flow system.

Statistical optimization of a DC–RF hybrid plasma flow system for in-flight particle treatment

Abstract There are many input parameters to control a DC–RF hybrid plasma flow system, such as total gas flow rate, central gas flow rate, swirl gas ratio, RF power and DC power. Furthermore, the interactive effects among these parameters should be considered. In the present study, statistical analysis using simple linear model is conducted to clarify the effects of the input parameters and their interactions on the outputs such as particle residence time and average temperature in a DC–RF hybrid plasma flow system. The thermofluid characteristics of a DC–RF hybrid plasma flow are compared with those of an RF plasma flow. It is shown that the plasma characteristics are changed drastically by adding even small DC power. Furthermore, controllability is also improved by optimizing the operating conditions of a DC–RF hybrid plasma flow system.

Statistical optimization of a DC–RF hybrid plasma flow system for in-flight particle treatment

There are many input parameters to control a DC–RF hybrid plasma flow system, such as total gas flow rate, central gas flow rate, swirl gas ratio, RF power and DC power. Furthermore, the interactive effects among these parameters should be considered. In the present study, statistical analysis using simple linear model is conducted to clarify the effects of the input parameters and their interactions on the outputs such as particle residence time and average temperature in a DC–RF hybrid plasma flow system. The thermofluid characteristics of a DC–RF hybrid plasma flow are compared with those of an RF plasma flow. It is shown that the plasma characteristics are changed drastically by adding even small DC power. Furthermore, controllability is also improved by optimizing the operating conditions of a DC–RF hybrid plasma flow system.

The movement and thermal history of an aluminium particle in a rf plasma generator

In previous studies on plasma-particle interaction, as far as we know,the rf plasma flow and temperature fields are all simulated by the non-self-consistentone-dimensional electromagnetic (1-D EM) field model. In the present paper, thecomplete self-consistent two-dimensional electromagnetic (2-D EM) field model in-corporating the axial Lorentz force component, which is neglected in the 1-D model,is firstly adopted to calculate the aluminium particle trajectory and thermal historyin atmospheric rf Ar plasma with the particle evaporation effect included. The cru-cial effect of reverse flow within the coil region on the particle trajectory is discoveredand the results show that the 2-D EM field model must be adopted instead of the1-D model when the plasma-particle interaction is studied. The effect of carrier gasflux on the particle movement and heating are also studied, resulting in some usefulconclusions for both plasma theory and application.

The movement and thermal history of an aluminium particle in a RF plasma generator

In previous studies on plasma-particle interaction, as far as we know, the rf plasma flow and temperature fields are all simulated by the non-self-consistent one-dimensional electromagnetic (1-D EM) field model. In the present paper, the complete self-consistent two-dimensional electromagnetic (2-D EM) field model incorporating the axial Lorentz force component, which is neglected in the 1-D model, is firstly adopted to calculate the aluminium particle trajectory and thermal history in atmospheric rf Ar plasma with the particle evaporation effect included. The crucial effect of reverse flow within the coil region on the particle trajectory is discovered and the results show that the 2-D EM field model must be adopted instead of the 1-D model when the plasma-particle interaction is studied. The effect of carrier gas flux on the particle movement and heating are also studied, resulting in some useful conclusions for both plasma theory and application.