Correlation of Spray Ring Data for Gas Atomization of Liquid Metals

In this article, the thermal history and cooling rate experienced by gas-atomized Al-based amorphous powders were studied via numerical simulations. Modeling simulations were based on the assumption of Newtonian cooling with forced convection, as well as an energy balance, which involves gas dynamics, droplet dynamics, and heat transfer between gas and droplet. To render the problem tractable, phase transformations, crystal nucleation, and growth were not taken into account in the analysis of the solidification of Al droplets; instead, an energy balance approach was formulated and used. The numerical results and associated analysis were used to optimize processing parameters during gas atomization of Al-based amorphous powder. The results showed that the cooling rate of droplets increases with decreasing powder size and can reach in excess of 10 5 K/s for powder <20 lm in diameter. Gas composition has a more significant influence on cooling rate than gas pressure, and 100 pct He has the highest cooling effect. The results also showed that the cooling rate increases with increasing melt superheat temperature.

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“…[21,[26][27][28][29] The mass probability density function p(d) of the droplet-size distribution can be expressed by [30][31][32] …”

Section: A Droplet Size Distributionmentioning

confidence: 99%

“…Another often used parameter for describing atomized power size is the mass median diameter d 50 , which is defined as the droplet size that corresponds to the 50 pct cumulative frequency. d 50 can be well predicted for gas atomizing Al alloys powder by using a correlation developed by Lubanska [27] :…”

Section: A Droplet Size Distributionmentioning

confidence: 99%

Gas Atomization of Amorphous Aluminum: Part I. Thermal Behavior Calculations

Zheng

Lin

Zhou

et al. 2009

Metall Mater Trans B

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“…This was consistent with previous results suggesting that the powder size exhibited a log-normal distribution. [10,36,40] 2. Powder size distribution by laser diffraction Alternatively, another optical technique, laser diffraction, can be applied to the collected sample.…”

Section: Postrun Analysis Of Spray Droplet Size Distribution Usingmentioning

confidence: 99%

Characterization of spray atomization of 3003 aluminum alloy during linear spray atomization and deposition

Zhou

Lee

McDonell

et al. 1998

Metall Mater Trans B

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Linear spray atomization and deposition is an attractive technique to produce near-net-shape deposits, such as aluminum sheet and strip. In the present study, phase Doppler interferometry (PDI) was used in a backscatter mode to characterize, in situ, the droplet size and velocity distributions during linear spray atomization and deposition of a 3003 aluminum alloy. The PDI measurements were obtained along axes corresponding to the direction parallel to the nozzle slit and to the direction perpendicular to the slit. The PDI results delineate the temporal and spatial distribution of the droplet size and velocity during the metal spray. Both point and ''line'' measurements were obtained and are reported. The line measurements resulted from the integration of measurement made along a line scan obtained in real time (i.e., not ensemble averaged). Postrun analysis of the droplet size distribution using laser diffraction and sieving techniques is also reported. The PDI point measurements revealed that droplet size and velocity distribution were relatively invariant with time. The line measurements of droplet velocity showed that the droplet axial velocity exhibits a bimodal behavior, which becomes more apparent with increasing atomizing gas pressure, a result of droplet recirculation inside the spray chamber. In addition, the peak in the droplet axial velocity distribution increased as atomizing gas pressure increased. The line characterization also showed that the droplet size distribution became more homogeneous with increasing gas pressure, and that the distribution characteristic diameters of droplets decreased consistently with increasing gas pressure. Postrun characterization of the droplet size distribution of the entire metal spray using diffraction and sieving methods indicated that the mass (volume) median diameter D 50 and the Sauter mean diameter (SMD) D 32 decreased with increasing gas pressure in a manner consistent with PDI results.

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“…The deposit shape is directly controlled by the mass flux profile of the nozzle Following the approaches reported earlier [ 1,3] water spray patternation was used extensively to determine the factors controlling the mass flux profiles of the spray.…”

Section: Mass Flux Profilesmentioning

confidence: 99%

Spray forming -- Aluminum: Third annual report (Phase 2). Technical progress -- Summary

Kozarek¹

1998

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Correlation of Spray Ring Data for Gas Atomization of Liquid Metals

Cited by 122 publications

References 2 publications

Gas Atomization of Amorphous Aluminum: Part I. Thermal Behavior Calculations

Gas Atomization of Amorphous Aluminum: Part I. Thermal Behavior Calculations

Characterization of spray atomization of 3003 aluminum alloy during linear spray atomization and deposition

Spray forming -- Aluminum: Third annual report (Phase 2). Technical progress -- Summary

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