Effect of gas flow rate on shapes of weld bead sections. Study on high‐speed surface treatment by arc with laser (2nd report)

2001 ◽  
Vol 15 (5) ◽  
pp. 345-353 ◽  
Author(s):  
A Utsumi ◽  
J Matsuda ◽  
M Yoneda ◽  
M Katsumura
Keyword(s):  
Surface Treatment ◽  
Flow Rate ◽  
High Speed ◽  
Gas Flow ◽  
Weld Bead ◽  
Gas Flow Rate

THE EFFECT OF NITROGEN GAS FLOW RATE ON THE PROPERTIES OF TiN-COATED HIGH-SPEED STEEL (HSS) USING CATHODIC ARC EVAPORATION PHYSICAL VAPOR DEPOSITION (PVD) TECHNIQUE

2005 ◽  
Vol 12 (04) ◽  
pp. 631-643 ◽  
Author(s):  
ALI MUBARAK ◽  
ESAH BINTI HAMZAH ◽  
MOHD RADZI HJ. MOHD TOFF ◽  
ABDUL HAKIM BIN HASHIM
Keyword(s):  
Flow Rate ◽  
Physical Vapor Deposition ◽  
High Speed ◽  
Gas Flow ◽  
High Speed Steel ◽  
Gas Flow Rate ◽  
Nitrogen Gas ◽  
Cathodic Arc Evaporation ◽  
Arc Evaporation ◽  
Cathodic Arc

Cathodic arc evaporation (CAE) is a widely-used technique for generating highly ionized plasma from which hard and wear resistant physical vapor deposition (PVD) coatings can be deposited. A major drawback of this technique is the emission of micrometer-sized droplets of cathode material from the arc spot, which are commonly referred to as "macroparticles." In present study, titanium nitride ( TiN ) coatings on high-speed steel (HSS) coupons were produced with a cathodic arc evaporation technique. We studied and discussed the effect of various nitrogen gas flow rates on microstructural and mechanical properties of TiN -coated HSS coupons. The coating properties investigated in this work included the surface morphology, thickness of deposited coating, adhesion between the coating and substrate, coating composition, coating crystallography, hardness and surface characterization using a field emission scanning electron microscope (FE-SEM) with energy dispersive X-ray (EDX), X-ray diffraction (XRD) with glazing incidence angle (GIA) technique, scratch tester, hardness testing machine, surface roughness tester, and atomic force microscope (AFM). An increase in the nitrogen gas flow rate showed decrease in the formation of macro-droplets in CAE PVD technique. During XRD-GIA studies, it was observed that by increasing the nitrogen gas flow rate, the main peak [1,1,1] shifted toward the lower angular position. Surface roughness decreased with an increase in nitrogen gas flow rate but was higher than the uncoated polished sample. Microhardness of TiN -coated HSS coupons showed more than two times increase in hardness than the uncoated one. Scratch tester results showed good adhesion between the coating material and substrate. Considerable improvement in the properties of TiN -deposited thin films was achieved by the strict control of all operational steps.

Hydrodynamic and Mass Transfer Parameters in Agitated Reactors Part I: Critical Mixing Speed, Induced Gas Flow Rate, and Wavy Surface in SARs and GIRs

2004 ◽  
Vol 2 (1) ◽  
Author(s):  
Romain Lemoine ◽  
Benoit Fillion ◽  
Badie I Morsi
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Gas Flow ◽  
High Pressures ◽  
Operating Conditions ◽  
Organic Liquids ◽  
Gas Flow Rate ◽  
Mixing Speed ◽  
Liquid Height ◽  
Critical Mixing

The critical mixing speed for gas entrainment (NCRE), for gas induction (NCRI), induced gas flow rate (QGI) as well as the wavy gas-liquid interfacial area (aWave) of N2 and air were measured in pure toluene and three mixtures of organic liquids (toluene-benzoic acid-benzaldehyde mixtures) under wide ranges of temperatures, T (300-453K), pressures, P (1-15 bar), mixing speeds, N (13.3-23.3Hz) and liquid heights, H (0.171-0.268m) using a 4-liter, see-through agitated autoclave operating as a surface-aeration reactor (SAR) and gas-inducing reactor (GIR).NCRE and NCRI as well as aWave were estimated by analyzing the videos taken with an on-line high-speed Phantom camera through the reactor’s Jerguson windows. In the GIR, QGI was determined using a highly sensitive Coriolis mass flow meter. The Central Composite Statistical Design and analysis technique was used to study the effect of operating conditions on these hydrodynamic parameters.NCRE and NCRI appeared to increase with liquid height and decrease with temperature, whereas, the pressure and gas nature did not significantly affect both parameters. The liquid physicochemical properties were found to strongly affect NCRE and NCRI, and QGI. Increasing mixing speed or decreasing liquid height increased QGI. Increasing temperature or decreasing liquid viscosity initially increased and then decreased QGI. Increasing pressure or gas density on the other hand decreased QGI. Increasing mixing speed and temperature or decreasing liquid height significantly enhanced aWave, as compared to the flat liquid surface. At high pressures, however, lower values of aWave were obtained. Empirical and statistical correlations were also developed to accurately predict NCRE, NCRI, QGI and aWave.

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.

On the Influence of Fluctuating Flow Rate Upon the Performance and Behaviour of Isothermal Reacting Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluidized Bed Reactor ◽  
Computational Techniques ◽  
Continuous Stirred Tank Reactor ◽  
Gas Flow Rate ◽  
Solid Reaction ◽  
Continuous Stirred Tank ◽  
And Performance ◽  
Reacting Systems

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.

scholarly journals Investigation on influences of loose gas on gas-solid flows in a circulating fluidized bed (CFB) reactor using full-loop numerical simulation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Pengju Huo ◽  
Xiaohong Li ◽  
Yang Liu ◽  
Haiying Qi
Keyword(s):  
Numerical Simulation ◽  
Flow Rate ◽  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Separation Efficiency ◽  
Circulation Rate ◽  
Solid Mass ◽  
Gas Flow Rate ◽  
Gas Leakage ◽  
Mass Circulation

AbstractThe influences of loose gas on gas-solid flows in a large-scale circulating fluidized bed (CFB) gasification reactor were investigated using full-loop numerical simulation. The two-fluid model was coupled with the QC-energy minimization in multi-scale theory (EMMS) gas-solid drag model to simulate the fluidization in the CFB reactor. Effects of the loose gas flow rate, Q, on the solid mass circulation rate and the cyclone separation efficiency were analyzed. The study found different effects depending on Q: First, the particles in the loop seal and the standpipe tended to become more densely packed with decreasing loose gas flow rate, leading to the reduction in the overall circulation rate. The minimum Q that can affect the solid mass circulation rate is about 2.5% of the fluidized gas flow rate. Second, the sealing gas capability of the particles is enhanced as the loose gas flow rate decreases, which reduces the gas leakage into the cyclones and improves their separation efficiency. The best loose gas flow rates are equal to 2.5% of the fluidized gas flow rate at the various supply positions. In addition, the cyclone separation efficiency is correlated with the gas leakage to predict the separation efficiency during industrial operation.

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