Transport characteristics of pulsating high-temperature particles based on vortex structure analysis by large-eddy simulation

Abstract

The pulsating high-temperature particles generated in the industrial production process are common pollutants in industrial buildings. Accurately grasping the transport characteristics of pulsating high-temperature particles is an important task to achieve high-efficiency industrial ventilation system design. In this study, large eddy simulation was used to study the transport characteristics of pulsating high-temperature particles with 5 μm ≤ dp ≤ 70 μm. The aspects discussed mainly include the temperature variations of pulsating high-temperature particles, the interaction between airflow vortex structure and particles, the influence of initial temperature (303 K ≤ T0 ≤ 1273 K) on particle transport range, and the proportion variations of different particle diameters in the work area. The results show that particles with different diameters present similar heating effects on airflow. The vorticity of vortex structure is attenuated by being transferred to both sides during transport. The vorticity attenuation causes the particle transport to occur horizontally from the inside of the vortex structure to the outside. The variations in the particle concentration caused by horizontal transport will affect the shape of the small-scale vortex structure at the edge. When 0.297 ≤ St0 ≤ 0.783, the increase of the initial temperature promotes the vortex structure to carry more particles from airflow to surroundings. When T0 = 1273 K, particles with 0.003 ≤ St0 ≤ 0.107 are transported to the upper space from work area, while particles with 0.107 <St0 ≤ 0.582 are suspended in work area. The results help guide the refined design of local exhaust ventilation.