焊接工艺多源散发的高温颗粒污染物扩散特性数值模拟

Numerical simulation of diffusion characteristics of high-temperature particles generated by multiple pollution sources in welding process

为探究热工艺过程产生的热气流作用下颗粒的迁移规律,基于气固两相离散粒子模型(DPM)对多源浮射流伴生的高温颗粒的扩散特性进行了数值研究,讨论了两相流运动过程中热气流与颗粒群的温度和速度的瞬时变化情况.结果表明,对于473K≤T_(0)≤673K的高温颗粒群,温度衰减趋势类似,颗粒群温度分布呈中心对称;当5μm≤d_(p)≤20μm时,颗粒与气流之间的跟随性随着粒径的增大而降低;热羽流随时间经历了独立发展和相互合并的过程,羽流之间涡旋结构的消失导致中心位污染源散发的d_(p)=10μm的颗粒更容易发生沉降.

In order to explore the migration law of particles under the action of hot airflow in the process of hot working,the diffusion characteristics of high-temperature particles associated with multiple buoyant jets are numerically studied based on the gas-solid two-phase discrete particle model(DPM).The instantaneous changes of the temperature and velocity of the hot airflow and the particle group during the two-phase flow are discussed.The results show that for the high-temperature particle group with 473K≤T_(0)≤673K,the temperature attenuation trend is similar,and the temperature distribution of the particle group is centrosymmetric.When the particle size is between 5μm and 20μm,the followability between particles and airflow decreases as the particle size increases.Thermal plumes have undergone independent development and merging processes over time.The disappearance of the vortex structure between the plumes causes the particles with a particle size of 10μm emitted by the central pollution source to settle moreeasily.