Modeling dispersion mode of high-temperature particles transiently produced from industrial processes

Abstract

High-temperature particles that are transiently produced at large concentrations become common contaminants in industrial buildings, and cause significant harm to worker health and indoor air quality. Along with high-temperature particle movement, ambient air will be heated and the airflow velocity distribution will change accordingly. Some particles will separate with the airflow, depending on the air velocity around particles and particle diameters. Therefore, different dispersion modes will occur. This study developed a numerical model to investigate particle dispersion in industrial buildings. Three dispersion modes were studied, with a consideration of the influence of initial temperature (T0) and particle diameter (dp). Particles with higher T0 and smaller dp (T0 = 673 K; and 1 μm ≤ dp ≤ 10 μm, respectively) were associated with significant horizontal diffusion. This included the movement of most particles within the upper space. Particles with either a larger dp and higher T0, or smaller dp and lower T0 (T0 = 673 K, dp = 30 μm and 293 K ≤ T0 ≤ 373 K, dp = 10 μm), experienced the least horizontal diffusion. Upward transport was limited, with the majority of the particles staying at lower levels. Particles for which T0 and dp ranged from T0 = 673 K, 10 μm ≤ dp ≤ 20 μm and 473 K ≤ T0 ≤ 573 K, dp = 10 μm, respectively, experienced moderate horizontal diffusion. Most particles moved in the upper-middle space and spent the longest time in the vertical direction. Our conclusions inform future studies focusing on human protection and ventilation system design.