scholarly journals Plasmachemical Synthesis of Nanopowders in the System Ti(O,C,N) for Material Structure Modification

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Michael Filkov ◽  
Andrei Kolesnikov
Keyword(s):  
Plasma Jet ◽  
Chemical Reactor ◽  
Plasma Jets ◽  
Titanium Carbonitride ◽  
Material Structure ◽  
Operational Parameters ◽  
Synthesis Conditions ◽  
Mixing Chamber ◽  
Butane Mixture ◽  
Computational Fluid Dynamics Cfd

Refractory nanoparticles are finding broad application in manufacturing of materials with enhanced physical properties. Production of carbide, nitride, and carbonitride nanopowders in high volumes is possible in the multijet plasmachemical reactor, where temperature and velocity distributions in reaction zone can be controlled by plasma jet collision angle and mixing chamber geometry. A chemical reactor with three Direct Current (DC) arc plasma jets intersecting at one point was applied for titanium carbonitride synthesis from titanium dioxide, propane-butane mixture, and nitrogen. The influence of process operational parameters on the product chemical and phase composition was investigated. Mixing conditions in the plasma jet collision zone, particles residence time, and temperatures were evaluated with the help of Computational Fluid Dynamics (CFD) simulations. The synthesized nanoparticles have predominantly cubic shape and dimensions in the range 10–200 nm. Phase compositions were represented by oxycarbonitride phases. The amount of free (not chemically bonded) carbon in the product varied in the range 3–12% mass, depending on synthesis conditions.

Validation of a 2D CFD Model for Hydrodynamics' Studies in CIJ Mixers

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Ricardo J. Santos ◽  
André M. Teixeira ◽  
Ertugrul Erkoç ◽  
Mohamed Sultan ◽  
Anna M Karpinska ◽  
...  
Keyword(s):  
Flow Field ◽  
Impinging Jets ◽  
Cfd Model ◽  
Operational Parameters ◽  
3D Flow ◽  
Cfd Simulations ◽  
Mixing Chamber ◽  
Validity Range ◽  
Computational Fluid Dynamics Cfd ◽  
2D Model

A 2D model of a confined impinging jets mixer having the same geometry of the mixing chamber of a Reaction Injection Moulding, RIM, machine is introduced for the flow field simulation in a Computational Fluid Dynamics, CFD, code. From the CFD simulations the flow field structures and dynamics are clearly established. In addition, the numerical parameters affecting the 2D model simulations are studied, setting for each parameter a validity range. The 2D model is validated and used in the study of some operational parameters: the Reynolds number, the Froude number and the momentum ratio between the opposed jets. The validation of the CFD simulations is also made by comparison with experimental results. The limitations of the 2D model, for simulating the actual 3D flow field, are assessed; from the 2D/3D comparison, it is clearly shown that the introduced model can predict the main flow field features.

scholarly journals High-Speed Video Analysis of the Process Stability in Plasma Spraying

2021 ◽  
Author(s):  
K. Bobzin ◽  
M. Öte ◽  
M. A. Knoch ◽  
I. Alkhasli ◽  
H. Heinemann
Keyword(s):  
Plasma Spraying ◽  
High Speed ◽  
Plasma Jet ◽  
Plasma Jets ◽  
Time Dependent ◽  
Acquisition Time ◽  
Fast Fourier Transformation ◽  
Frequency Spectra ◽  
Dependent Signal ◽  
The Stability

AbstractIn plasma spraying, instabilities and fluctuations of the plasma jet have a significant influence on the particle in-flight temperatures and velocities, thus affecting the coating properties. This work introduces a new method to analyze the stability of plasma jets using high-speed videography. An approach is presented, which digitally examines the images to determine the size of the plasma jet core. By correlating this jet size with the acquisition time, a time-dependent signal of the plasma jet size is generated. In order to evaluate the stability of the plasma jet, this signal is analyzed by calculating its coefficient of variation cv. The method is validated by measuring the known difference in stability between a single-cathode and a cascaded multi-cathode plasma generator. For this purpose, a design of experiment, covering a variety of parameters, is conducted. To identify the cause of the plasma jet fluctuations, the frequency spectra are obtained and subsequently interpreted by means of the fast Fourier transformation. To quantify the significance of the fluctuations on the particle in-flight properties, a new single numerical parameter is introduced. This parameter is based on the fraction of the time-dependent signal of the plasma jet in the relevant frequency range.

scholarly journals Tiny Cold Atmospheric Plasma Jet for Biomedical Applications

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 249
Author(s):  
Zhitong Chen ◽  
Richard Obenchain ◽  
Richard E. Wirz
Keyword(s):  
Biomedical Applications ◽  
Plasma Jet ◽  
Discharge Voltage ◽  
Plasma Jets ◽  
Atmospheric Plasma ◽  
Physical Parameters ◽  
Cold Atmospheric Plasma ◽  
Water Metal ◽  
Plasma Probe ◽  
Jet Nozzle

Conventional plasma jets for biomedical applications tend to have several drawbacks, such as high voltages, high gas delivery, large plasma probe volume, and the formation of discharge within the organ. Therefore, it is challenging to employ these jets inside a living organism’s body. Thus, we developed a single-electrode tiny plasma jet and evaluated its use for clinical biomedical applications. We investigated the effect of voltage input and flow rate on the jet length and studied the physical parameters of the plasma jet, including discharge voltage, average gas and subject temperature, and optical emissions via spectroscopy (OES). The interactions between the tiny plasma jet and five subjects (de-ionized (DI) water, metal, cardboard, pork belly, and pork muscle) were studied at distances of 10 mm and 15 mm from the jet nozzle. The results showed that the tiny plasma jet caused no damage or burning of tissues, and the ROS/RNS (reactive oxygen/nitrogen species) intensity increased when the distance was lowered from 15 mm to 10 mm. These initial observations establish the tiny plasma jet device as a potentially useful tool in clinical biomedical applications.

scholarly journals Interferometric investigations of influence of target irradiation on the parameters of laser-produced plasma jets

2007 ◽  
Vol 25 (3) ◽  
pp. 425-433 ◽  
Author(s):  
A. Kasperczuk ◽  
T. Pisarczyk ◽  
S. Borodziuk ◽  
J. Ullschmied ◽  
E. Krousky ◽  
...  
Keyword(s):  
Focal Spot ◽  
Laser Energy ◽  
Plasma Jet ◽  
Plasma Jets ◽  
Plasma Expansion ◽  
Third Harmonic ◽  
Fundamental Process ◽  
Laser Produced Plasma ◽  
Laser Facility ◽  
Planar Target

Our recent experimental results demonstrate that the formation of plasma jets is a fundamental process accompanying the laser produced plasma expansion, if a massive planar target with relatively high atomic number is irradiated by a defocused laser beam. In this paper some new results on the influence of target irradiation conditions on plasma jet parameters are presented. The experiment was carried out at the PALS iodine laser facility, with the third harmonic beam of the pulse duration of 250 ps (FWHM). The beam energies varied in the range of 13–160 J, the focal spot radii in the range of 35–600 µm. The planar massive targets used in the experiment were made of Cu, Ag and Ta. For measurements of the electron density evolution a three frame interferometric system was employed. The jets were observed in the whole range of the laser energy used. The initial velocities of the plasma jets produced in the reported experiment reached the value of up to 7·107 cm/s, the jets were up to 4 mm long including the jet pedestal and about 400 µm in diameter. Calculations of the efficiency of the plasma jet production show that it decreases with increasing the laser energy.

scholarly journals Thermal behavior of ceramic particles in a gaseous medium at high temperature

2020 ◽  
Vol 307 ◽  
pp. 01056
Author(s):  
Abderrahmane AISSA ◽  
Abdel-Nour ZAIM ◽  
M SAHNOUN ◽  
Redouane FARES ◽  
M ABDELOUHAB ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Spherical Particle ◽  
Atmospheric Pressure ◽  
Computational Analysis ◽  
Gaseous Medium ◽  
Plasma Jet ◽  
Spray Process ◽  
Plasma Spray Process ◽  
Proposed Model ◽  
Computational Fluid Dynamics Cfd

Numerical simulation of the interaction between the spherical particle and plasma gas is carried out. The aim of this study is to investigatethermal transfer between the plasma gas and solid particle during the plasma spray process and to validate the well-known empirical correlation of the Ranz and Marshall. In the conditions of molten or semi-molten states of prepared substrate, the medium (plasma jet) can affect the high velocities of particles. On the basis of direct numerical simulation, the computational analysis has been carried out by using computational fluid dynamics (CFD) of heat transfer in atmospheric pressure and mid-temperature range (3000k–12000k) of a plasma flow over a spherical particle. Our proposed model improves correlation with experiments compared to the existing approaches in the literature.

scholarly journals Theoretical and Experimental Performance Analysis of a Novel Domestic Biogas Burner

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Lucia M. Petro ◽  
Revocatus Machunda ◽  
Siza Tumbo ◽  
Thomas Kivevele
Keyword(s):  
Rural Areas ◽  
Large Scale ◽  
Fossil Fuels ◽  
Water Boiling Test ◽  
Agricultural Mechanization ◽  
Cooking Process ◽  
Mixing Chamber ◽  
Gas Consumption ◽  
Computational Fluid Dynamics Cfd ◽  
Low Efficiency

The inefficient indoor burning of fuelwood on traditional cookstoves generates pollutants, primarily carbon monoxide and many other human health-damaging emissions. It is from this risk that it is necessary to have an immediate shift to alternative cleaner fuel sources. Biogas, which is among the biofuels from biomass, is one of the resources that play a considerable part in a more diverse and sustainable global energy mix. For domestic purposes in rural areas of Tanzania, biogas provides a better option that can supplement the use of fossil fuels such as wood, charcoal, and kerosene, which is nonrenewable. However, the low efficiency experienced in the locally made biogas burners hinders the large-scale use of biogas among the population in the country. With the locally made burners, the users of biogas for the domestic application face problems including heat loss and high gas consumption which affects the whole cooking process. It is against this backdrop that the current study objectives incline on designing and improving the efficiency of the locally manufactured burners to achieve the uniform flow of fuel in the mixing chamber, which will result to the consistent heat distribution around the cooking pot. The optimization of the burner was done by using computational fluid dynamics (CFD) through varying the number of flame portholes and air holes as well as the size of the jet before fabrication. The increased efficiency of the burner has also contributed by the addition of the fuel distributor. The results showed that the optimum hole diameter of the jet was 2.5 mm and that of the manifold was 100 mm. The currently developed biogas burner was tested and compared with the other two locally made burners. The water boiling test (WBT) on these three burners showed that the developed burner has a thermal efficiency of 67.01% against 54.61% and 58.82% of the Centre for Agricultural Mechanization and Rural Technology (CARMATEC) and Simgas, respectively. Additionally, the fuel consumption of the developed burner was 736 g/L as compared to 920 g/L for CARMARTEC and 833 g/L for that of Simgas. The developed burner and its corresponding cookstove are both environmentally friendly and economical for household utilization in Tanzania and other developing countries.

scholarly journals Tailoring the Chemistry of Plasma-Activated Water Using a DC-Pulse-Driven Non-Thermal Atmospheric-Pressure Helium Plasma Jet

Plasma ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 127-137 ◽  
Author(s):  
Oh ◽  
Szili ◽  
Hatta ◽  
Ito ◽  
Shirafuji
Keyword(s):  
Hydrogen Peroxide ◽  
Atmospheric Pressure ◽  
Pulse Width ◽  
Plasma Jet ◽  
Plasma Jets ◽  
Helium Plasma ◽  
Uv Absorption Spectroscopy ◽  
Pulse Polarity ◽  
Plasma Activated Water

We investigate the use of a DC-pulse-driven non-thermal atmospheric-pressure He plasma jet in the regulation of hydrogen peroxide (H2O2), nitrite (NO2−), nitrate (NO3−), and oxygen (O2) in deionized (DI) water. The production of these molecules is measured by in situ UV absorption spectroscopy of the plasma-activated water (PAW). Variations in the pulse polarity and pulse width have a significant influence on the resultant PAW chemistry. However, the trends in the concentrations of H2O2, NO2−, NO3−, and O2 are variable, pointing to the possibility that changes in the pulse polarity and pulse width might influence other plasma variables that also impact on the PAW chemistry. Overall, the results presented in this study highlight the possibility of using DC-pulse-driven plasma jets to tailor the chemistry of PAW, which opens new opportunities for the future development of optimal PAW formulations across diverse applications ranging from agriculture to medicine.

scholarly journals Applications of the COST Plasma Jet: More than a Reference Standard

Plasma ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 316-327 ◽  
Author(s):  
Gorbanev ◽  
Golda ◽  
Gathen ◽  
Bogaerts
Keyword(s):  
Chemical Properties ◽  
Plasma Jet ◽  
Plasma Jets ◽  
Physical And Chemical Properties ◽  
Reference Standard ◽  
Liquid Systems ◽  
Plasma Research ◽  
The Cost ◽  
Physical And Chemical ◽  
And Chemical Properties

The rapid advances in the field of cold plasma research led to the development of many plasma jets for various purposes. The COST plasma jet was created to set a comparison standard between different groups in Europe and the world. Its physical and chemical properties are well studied, and diagnostics procedures are developed and benchmarked using this jet. In recent years, it has been used for various research purposes. Here, we present a brief overview of the reported applications of the COST plasma jet. Additionally, we discuss the chemistry of the plasma-liquid systems with this plasma jet, and the properties that make it an indispensable system for plasma research.

Sign in / Sign up

Export Citation Format

Share Document