罩间存在障碍物的吹吸罩流场三维数值模拟

3D numerical simulation of the flow field with push-pull hoods containing barriers between them

为了使吹吸罩达到对污染物的最佳控制,以某企业电镀生产线上行车行进过程中由于镀件表面黏附高浓度槽液而造成室内环境污染为实物模型,建立吹吸罩口间存在障碍物的三维数学模型,利用Fluent计算动力学软件对不同吹风口风速和吸风口风速下的排风罩流场进行数值模拟,经比较确定最佳联合速度,并将模拟结果与经典吹吸速度分布图及试验条件下所测得的污染气体质量分数进行对比分析。结果表明,所建立数学模型是合理的,所确定的最佳效果时的相关参数与经典理论基本一致,可用于工程实际。

This paper attempts to propose a 3D numerical simulation model of the flow field with push-pull hoods containing barriers between them in hoping to solve the problem of the dispersion of contaminants. As is known, the dispersion of contaminants in different sections of an apparatus can be controlled effectively via a pul-l push hood powered by a jet flow. Actually, such device has already been widely used in places where contaminants are serious but can not be eliminated. The said push-pull hoods are usually armed with the fo-l lowing features： minute air volume, perfect pollution control, powerful ant-i jam behavior, free from the impact of the process operations. Although no barrierswere considered in the former design between the push hood and pull hood in the regular production process according to the processing demands, we still feel it necessary to stress the demand for them, for it is necessary to choose the best velocity of push hood and pull hood to control the containments. Based on the above starting point, we have chosen the computational fluid dynamics （CFD） model to solve the problem. First of all, we have taken the contaminants accumulated in the painted work-pieceswith very harmful content adhered in them as a physical model, while assuming that geometrical models are set by the GAMBIT code. Along with it, let the appropriate meshes generated in such a way that the mesh intervals with added source terms of 0.025 m, cover 0.1 m and a wall of large space of 0.2 m. And, then, try to separate the wall face by paving triangle grids and the volumeT-grids. Furthermore, partial grids near the cover and the work-piece can be separated with shorter intervals to increase the precision and convergence speed of calculation. Thus, the whole computational domain can be separated into 300 000 computational cells. In doing so, we have chosen the standardk-εturbulent model to simulate the near-ground contaminant dispersion. While achieving the best joint velocity from the simulation, we have compared our simulation results with the classical velocity profile correlation and the pollutant concentration laid out in our experiment with the push and pull air flow. And, finally, the results show that the simulation results, the theoretical results and the experiment results come in full conformitywith each other. Thus, we have successfully proved the soundness of our mathematical model for the push-pull hood, which can be used in the corresponding engineering fields.