High Efficient Ventilation System of Metallic for Conservation of the Working Environment in a Fabrication Shop

最近，随着对环境问题的高度关注，人们倾向于重新考虑目前的工作环境。特别是在切割和打井过程中产生的金属烟雾对空气的污染是劳动健康不可避免的问题。为了解决这一问题，有必要设计合适的通风系统，由于车间容量大，通风系统一般由大型高效设备组成。然而，作为微小颗粒的烟气的物理性质和运动特性至今还没有得到准确的掌握。本研究以建立完善的烟气控制通风系统为目的，通过实验手段和数值计算，阐明了在紊流中假设微小颗粒为气相驱动通风机在烟气上的输运现象。因此，本文采用基于SIMPLE算法的k-ε模型，对湍流气流中没有平流作用时，热烟有形成停滞状态的湍流扩散状态进行了数值分析。同时，根据相应的相似律，对加工车间的准二维模型中有色盐水对烟气扩散进行了实验模拟。在此基础上，采用适当的相似律对加工车间的三维模型进行了烟雾发生器扩散的实验模拟。烟气流动的实验结果与用双层区模型计算的热、烟扩散状态的结果吻合较好。利用实验数据对某加工车间通风系统与烟气输送状态的关系进行了较深入的研究。

Recently, the present working environment tends to be reconsidered with high interest in the environmental problem. Especially, air pollution by generating metallic fume during the progress of cutting and welling is the unavoidable issue for labor health. For settling this matter, it is necessary to design the suitable ventilation system that is desirable to be generally composed of large scaled equipments with high efficiency due to big capacity of a fabrication shop. However, the physical property and movement characteristic of fume as minute particles have not been grasped accurately even now.In this study, with a view to establishing the ventilation system with perfect control of fume flow, the transportation phenomena on fume, that are assumed minute particles to be gas-phase in turbulent flow by driving vent fans, would be clarified using experimental means and numerical calculation.Hence, the numerical analysis on the turbulent diffusion state of heat and fume, in which it has tendency to form those stagnant in absence of advection effect on turbulent gas flow, are carried out by k-ε model based on SIMPLE algorithm. Also, the experimental simulations of fume diffusion using pigmented salt water in the quasi-two dimensional models of fabrication shop are executed with the appropriate similarity law.Furthermore, the experimental simulations of fume diffusion using smoke generator in the three dimensional models of fabrication shop are executed with the appropriate similarity law. And the experimental result of fume flow shows considerably good agreement with, the calculated data using two-layers Zone model on the diffusion state of heat and fume. The relation between the ventilation system and the fume transportation state in a fabrication shop is investigated evidently using experimental data.