scholarly journals Modelling of a Non-Transferred Plasma Torch Used for Nano-Silica Powders Production

2021 ◽  
Vol 11 (21) ◽  
pp. 9842
Author(s):  
Ibrahim A. AlShunaifi ◽  
Samira Elaissi ◽  
Imed Ghiloufi ◽  
Seham S. Alterary ◽  
Ahmed A. Alharbi
Keyword(s):  
Flow Rate ◽  
Plasma Torch ◽  
Gas Flow ◽  
Fine Powder ◽  
Nitrogen Plasma ◽  
Process Conditions ◽  
Core Diameter ◽  
Operation Conditions ◽  
Energy Current ◽  
Continuity Equations

In this study, a two-dimensional numerical model was developed to simulate operation conditions in the non-transferred plasma torch, used to synthesis nanosilica powder. The turbulent magnetohydrodynamic model was presented to predict the nitrogen plasma flow and heat transfer characteristics inside and outside the plasma torch. The continuity, momentum, energy, current continuity equations, and the turbulence model were expressed in cylindrical coordinates and numerically solved by COMSOL Multiphysics software with a finite element method. The operation conditions of the mass flow rate of ionized gas ranging from 78 sccm to 240 sccm and the current varying between 50 A to 200 A were systematically analyzed. The variation in the electrothermal efficiency with the gas flow rate, the plasma current, and the enthalpy was also reported. The results revealed that the increase in working current lead to a raise in the effective electric power and then an increase in the distribution of plasma velocity and temperature. The efficiency of the torch was found to be between 36% and 75%. The plasma jet exited the nozzle torch with a larger fast and hot core diameter with increasing current. The numerical results showed good correlation and good trends with the experimental measurement. This study allowed us to obtain more efficient control of the process conditions and a better optimization of this process in terms of the production rate and primary particle size. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the primary nanosilica powder that was experimentally collected. The arc plasma method enabled us to produce a spherical silicon ultra-fine powder of about 20 nm in diameter.

A Study on the Effect of Process Parameters on Surface Topography of Al Thin Films on Various Substrates Using AFM

2011 ◽  
Vol 383-390 ◽  
pp. 903-908
Author(s):  
S. Shanmugan ◽  
D. Mutharasu ◽  
Z. Hassan ◽  
H. Abu. Hassan
Keyword(s):  
Thin Films ◽  
Surface Topography ◽  
Flow Rate ◽  
Gas Flow ◽  
Process Conditions ◽  
Gas Flow Rate ◽  
Glass Substrates ◽  
Sputtering Power ◽  
Large Particles ◽  
Ar Gas

Al thin films were prepared over different substrates at various process conditions using DC sputtering. The surface topography of all prepared films was examined using AFM technique. Very smooth, uniform and dense surface were observed for Al films coated over Glass substrates. The observed particle size was nano scale (20 -70 nm) for Glass substrates. Sputtering power showed immense effect on surface roughness with respective to Ar gas flow rate. Noticeable change on surface with large particles was observed in Copper substrates at various sputtering power and gas flow rate.

Experimental Analysis of Venturi-Tube Behavior in Wet Gas Conditions

2020 ◽  
Author(s):  
Olav Mehlum ◽  
Øyvind Hundseid ◽  
Lars E. Bakken
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Volume Fraction ◽  
Volume Flow Rate ◽  
Venturi Tube ◽  
Low Flow ◽  
Detailed Knowledge ◽  
Operation Conditions ◽  
Wet Gas ◽  
Compressor Inlet

Abstract Subsea wet gas compressors have been successfully in operation for approximately 5 years. Their use has proven to increase the recovery by approximately 10% and achieve a reliability up to 98%. Further developed and operation of subsea wet gas compression require detailed knowledge of compressor operability and how shift in operational conditions affect the compressor system. The compressors ability to handle wet gas is documented in detail for a gas volume fraction limited down to 0.90. The 4–5 last year of operation proves the wet gas concepts capability. As years pass by, well pressure and production rate declines which causes the compressor operation point to shift towards the high head and low flow (surge) area of the characteristics. In addition, compressor inlet transients increase due to pipe surge (slugs), requiring a robust control system to prevent instabilities, e.g. compressor surge. It is therefore vital to understand how the compressor inlet flow device behaves at different wet operation conditions. The article documents how a standard dry gas venturi tube behave at different wet gas operation conditions. The venturi is designed according to ISO5167-4 for dry gas conditions and is tested at the low-pressure air water compressor test rig at NTNU. The primary objective of the work has been to visualize the wet flow regime through the transparent venturi tube and to document the wet gas flow rate measurements by means of single-phase meters. The venturi tube is tested in a GMF range from 1 to 0.83 at an air volume flow rate of 1.3m3/s.

Experimental Study on Mixing in Gas-Stirred Ladles with and without the Slag Phase through a Water Physical Model

2012 ◽  
Vol 1373 ◽  
Author(s):  
Adrián M. Amaro-Villeda ◽  
Jorge A. González Bello ◽  
Marco A. Ramírez-Argáez.
Keyword(s):  
Physical Model ◽  
Flow Rate ◽  
Gas Flow ◽  
Mixing Time ◽  
Steel Slag ◽  
Slag Layer ◽  
Process Conditions ◽  
Steel Ladle ◽  
Gas Flow Rate ◽  
Water Gas

ABSTRACTA 1/6th gas–stirred water physical model of a 140 ton steel ladle is used to evaluate mixing in air–water and air–water–oil systems to model argon–steel and argon–steel–slag systems respectively. Thickness of the slag layer is kept constant at 0.004 m. The effect of the gas flow rate (7, 17, and 37 l/min), plug position (0, 1/3, ½, and 2/3 of the ladle radius, R), and number of plugs (1, 2, and 3) on mixing time is also analyzed in this work. Gas is injected at the bottom of the ladle under several plug configurations varying both position and number of plugs. Chemical uniformity of 95% is selected as mixing criterion. Mixing times are experimentally determined when a tracer is suddenly injected into the ladle and the model is instrumented with a pH meter to track the time evolution of the tracer concentration (NaOH 1 M solution) in a given location inside the ladle. Process conditions for best mixing in both water–gas and water-gas–slag systems are: a single plug located at 2/3 of the ladle radius with a gas flow rate of 17 l/min.

Production of Size-Selected CuXSn1-X Nanoclusters

2011 ◽  
Vol 295-297 ◽  
pp. 70-73 ◽  
Author(s):  
Ahmad I. Ayesh ◽  
Naser Qamhieh ◽  
Saleh Thaker Mahmoud ◽  
Hussain Alawadhi
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Discharge Power ◽  
Inert Gas ◽  
Gas Flow Rate ◽  
Quadrupole Mass ◽  
Gas Condensation ◽  
Operation Conditions ◽  
Source Operation ◽  
Production Mechanisms

Composites of copper–tin (CuxSn1-x) nanoclusters were synthesized using the magnetron dc sputtering gas–condensation technique. Targets with controlled ratios of Sn to Cu were used to produce CuxSn1-xwith different compositions. The effects on the nanocluster size and yield of the sputtering discharge power, inert gas flow rate, and aggregation length were investigated using a quadrupole mass filter. The sputtering discharge power was optimized to maximize the nanocluster yield. The results show that as the inert gas flow rate increases the nanocluster size increases and then decreases. These dependences could be understood in terms of the dominant nanocluster production mechanisms. This work demonstrates the ability of controlling the CuxSn1-xnanoclusters’ size and composition by optimizing the source operation conditions.

Three-Dimensional Arc Modeling inside Non-Transferred Plasma Torch

2012 ◽  
Vol 217-219 ◽  
pp. 1407-1410
Author(s):  
Hai Ling Han ◽  
Qing Lin Wang
Keyword(s):  
Flow Rate ◽  
Plasma Torch ◽  
Gas Flow ◽  
Numerical Models ◽  
Three Dimensional ◽  
Arc Length ◽  
Gas Flow Rate ◽  
Three Dimensional Model ◽  
Anode Spot ◽  
The Given

Numerical models have been developed to study the characteristics of an arc inside the non-transferred plasma torch. A few of them have considered the diameter of anode spot and arc length in given current and gas flow rate. In this work, a three-dimensional model is developed to simulate power and entropy in the given current and diameter of anode spot. Different combinations of diameter of anode spot and arc length can produce torch power that corresponds to given current and gas flow rate. From the possible combinations of the diameter of anode spot and arc length predicted for given current and gas flow rate, the most feasible combination is obtained.

SCIENTIFIC AND ENGINEERING PRINCIPLES OF EFFICIENT FUEL USE AND ENVIRONMENTALLY FRIENDLY GAS COMBUSTION IN STOVE PLATES. PART 1. MODERN STATE-OF-THE-ART AND DIRECTIONS FOR IMPROVEMENT THE GAS BURNING IN DOMESTIC GAS COOKERS

2017 ◽  
pp. 3-18 ◽  
Author(s):  
B.S. Soroka ◽  
V.V. Horupa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Gas Flow ◽  
Renewable Energy Sources ◽  
Combustion Process ◽  
Orifice Diameter ◽  
Firing Process ◽  
Gas Flow Rate ◽  
Gas Combustion ◽  
Gas Stoves

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.

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