紀要論文

紀要論文

text

Transactions of JWRI.42(1) p.1-p.9

Influence of Particle Charging on the Fume Formation Process in Arc Welding

英語

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2013-06

In order to clarify the influence of electrostatic forces caused by charging of particles on the coagulation process in fume formation in arc welding, a previously-developed fume formation model has been modified to consider the influence of charging, for both local thermodynamic equilibrium (LTE) and non-LTE conditions. The model takes into account formation of the particles from metal vapour by nucleation, growth of the particles by condensation of metal vapour, and coagulation of the particles by collisions to form secondary particles. Results have been obtained for both ballistic and Brownian motion of the particles. It was found that the growth of secondary particles is suppressed when the average particle charge becomes significant, because charging of the particle hinders collisions among secondary particles through the strong repulsive electrostatic force. Furthermore, deviations from LTE strongly affect the coagulation process, because the increased electron density at a given gas temperature increases the charging of particles. Brownian motion leads to larger secondary particles, since the average particle speed is increased. The influence of Brownian motion and particle charging cancel each other to a large extent, particularly when deviations from LTE are considered.

application/pdf

Influence of Particle Charging on the Fume Formation Process in Arc Welding

英語

2013-06

Transactions of JWRI

42

1

1

9

03874508

https://hdl.handle.net/11094/26599