Effects of shielding gas temperature and flow rate on the welding fume particle size distribution

2017 ◽  
Vol 114 ◽  
pp. 55-61 ◽  
Author(s):  
V.I. Vishnyakov ◽  
S.A. Kiro ◽  
M.V. Oprya ◽  
A.A. Ennan
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Flow Rate ◽  
Welding Fume ◽  
Shielding Gas ◽  
Gas Temperature

scholarly journals Numerical Simulations of Molten Breakup Behaviors of a de Laval-Type Nozzle, and the Effects of Atomization Parameters on Particle Size Distribution

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1027
Author(s):  
Lianghui Xu ◽  
Xianglin Zhou ◽  
Jinghao Li ◽  
Yunfei Hu ◽  
Hang Qi ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Gas Flow ◽  
Nozzle Geometry ◽  
Particle Model ◽  
Process Conditions ◽  
Operating Pressure ◽  
Gas Temperature ◽  
Tracking Model

In this work, an atomizer with a de Laval-type nozzle is designed and studied by commercial computational fluid dynamics (CFD) software, and the secondary breakup process during atomization is simulated by two-way coupling and the discrete particle model (DPM) using the Euler-Lagrange method. The simulation result demonstrates that the gas flow patterns greatly change with the introduction of liquid droplets, which clearly indicates that the mass loading effect is quite significant as a result of the gas-droplet interactions. An hourglass shape of the cloud of disintegrating molten metal particles is observed by using a stochastic tracking model. Finally, this simulation approach is used for the quantitative evaluation of the effects of altering the atomizing process conditions (gas-to-melt ratio, operating pressure P, and operating gas temperature T) and nozzle geometry (protrusion length h, half-taper angle α, and gas slit nozzle diameter D) on the particle size distribution of the powders produced.

scholarly journals Encapsulation of Menthol in Beeswax by a Supercritical Fluid Technique

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Linjing Zhu ◽  
Hongqiao Lan ◽  
Bingjing He ◽  
Wei Hong ◽  
Jun Li
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Flow Rate ◽  
Saturated Solution ◽  
Narrow Particle Size Distribution ◽  
Solution Flow Rate ◽  
Process Conditions ◽  
Solution Flow ◽  
Expansion Temperature

Encapsulation of menthol in beeswax was prepared by a modified particles from gas-saturated solutions (PGSS) process with controlling the gas-saturated solution flow rate. Menthol/beeswax particles with size in the range of 2–50 μm were produced. The effects of the process conditions, namely, the pre-expansion pressure, pre-expansion temperature, gas-saturated solution flow rate, and menthol composition, on the particle size, particle size distribution, and menthol encapsulation rate were investigated. Results indicated that in the range of studied conditions, increase of the pressure, decrease of the gas-saturated solution flow rate, and decrease of the menthol mass fraction can decrease the particle size and narrow particle size distribution of the produced menthol/beeswax microparticles. An N2-blowing method was proposed to measure the menthol release from the menthol/beeswax microparticles. Results showed that the microparticles have obvious protection of menthol from its volatilization loss.

Determining Aerosol Particle Size Distribution Using Time-Resolved Laser-Induced Incandescence

2006 ◽  
Author(s):  
K. J. Daun ◽  
B. J. Stagg ◽  
F. Liu ◽  
G. J. Smallwood ◽  
D. R. Snelling
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Nano Particles ◽  
Solution Stability ◽  
Gas Temperature ◽  
Time Resolved ◽  
Laser Induced Incandescence ◽  
Ill Posed ◽  
Aerosol Volume

Time-resolved laser-induced incandescence is a powerful tool for determining the physical characteristics of aerosol dispersions of refractory nano-particles. In this procedure, particles within a small aerosol volume are heated with a nano-second laser pulse, and the temporal incandescence of the particles is then measured as they return to the ambient gas temperature. It is possible to infer particle size distribution from the temporal decay of the LII signal since the cooling rate of an individual particle depends on its area-to-volume ratio. This requires solving a mathematically ill-posed inverse problem, however, since the measured LII signal is due to the incandescence contributed by all particle sizes within the aerosol volume. This paper reviews techniques proposed in the literature for recovering particle size distributions from time-resolved LII data. The characteristics of this ill-posed problem are then discussed in detail, particularly the issues of solution stability and uniqueness. Finally, the accuracy and stability of each method is evaluated by performing a perturbation analysis, and the overall performance of the techniques is compared.

Difference in Filling Property between Two Types of Binder Treated Powders Made of Atomized or Reduced Iron Powder

2007 ◽  
Vol 534-536 ◽  
pp. 1613-1616
Author(s):  
Satoshi Uenosono ◽  
Yukiko Ozaki
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Iron Powder ◽  
Flow Rate ◽  
Reduced Iron Powder ◽  
Iron Based ◽  
The One

The filling property of the binder treated iron based powder made of atomized iron powder was compared with that of the one made of reduced iron powder. The latter one showed a better filling property than the former one, although the original reduced powder showed a worse flow rate. Changing the particle size distribution of the original atomized powder from wide to narrow like the original reduced iron powder, improved the filling property of the binder treated powder. As a result, the particle size distribution of the original iron powder was found to strongly affect the filling property of the binder treated powder.

Influence of Granulation Liquid Flow Rate on Particle-Size Distribution in Spray-Granulated Products

1977 ◽  
Vol 66 (10) ◽  
pp. 1462-1464 ◽  
Author(s):  
Ashok Mehta ◽  
Kenneth Adams ◽  
M.A. Zoglio ◽  
J.T. Carstensen
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate

Influence of Impactor Operating Flow Rate on Particle Size Distribution of Four Jet Nebulizers

2007 ◽  
Vol 12 (4) ◽  
pp. 353-359 ◽  
Author(s):  
Yue Zhou ◽  
Trevor L. Brasel ◽  
Dean Kracko ◽  
Yung-Sung Cheng ◽  
Amitkumar Ahuja ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Flow Rate ◽  
Jet Nebulizers

Study on Coal Particle Combustion Characteristics and NO Emission in a Hot Laminar Gas Flow

2017 ◽  
Author(s):  
MingYan Gu ◽  
Dawei Yan ◽  
XianHui He ◽  
Dan Yan ◽  
FengShan Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Coal Particle ◽  
Gas Flow ◽  
Combustion Process ◽  
Mass Ratio ◽  
Gas Temperature ◽  
Uniform Size ◽  
Coal Particles

The combustion and NO formation characteristics of coal particles of different size distributions in a laminar gas flow were investigated by numerical simulation. The variation of coal particle size distribution was obtained by changing the mass ratio of small-sized coal to large-sized coal. The gas-phase combustion was modeled using GRI-Mech 3.0. The particle motion was simulated using a trajectory model. The results show that the coal particle size distribution has a significant impact on combustion process and NO distribution. Coal particles of uniform size at either 105 or 75 μm results in a higher NO concentration than coal consisting of both the large and the small particles. The smaller-sized coal particles experience a rapid volatile release, a higher maximum gas temperature, and a higher maximum NO concentration. Increasing the mass ratio of the smaller-sized coal particles changes the gas temperature and the averaged NO distribution and lowers the maximum NO concentration.

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