Simulation of the evolution of agglomerated SiO2 particles in thermal plasma flow

The paper studies the behavior of agglomerated SiO2 particles in thermal plasma processing. The main stages are determined for their transformation to the hollow melt droplets. The proposed model, which includes partial encapsulation of gas, allows describing and analyzing the evolution stages for the particle size and the shell thickness in the ranges of 50-150 μm agglomerated particles and their 0.2-0.6 porosity.

Heat and Mass Transfer in Porous Particle in Thermal Plasma Flow

The paper presents research into heat and mass transfer in agglomerated particles exposed to the thermal plasma flow. The dynamic motion, heating and melting are considered for agglomerated particles. It is shown that the surface temperature of porous particles rather rapidly reaches the value of Tsur>Tmelt starting from the area of their introduction into the plasma flow. This effect is determined by the low conductivity of porous particles and indicates to a great temperature difference between the particle surface and its nucleus. It is shown that hollow particles can be obtained from silica sand treated by thermal plasma at 6700 K and 515 m/s velocity. The particle surface displays no clear defects. According to the analysis of X-ray diffraction patterns, the obtained hollow particles have no diffraction peaks.