水泥工业每年粉尘排放量约占全国工业粉尘排放量的40%，是我国主要大气粉尘污染源。随着国家对水泥行业粉尘排放量的一再严格限定，水泥行业在生产技术与除尘技术方面有了飞速发展。但是，目前除尘技术重点集中在原材料制备、熟料烧成、水泥包装上，而对袋装水泥运输，尤其对半封闭式车间袋装水泥转载点处产生的粉尘关注较少，这些地点的粉尘多是无组织排放。所以解决包装车间转载点处扬尘问题，对于改善员工工作环境有着重要的意义。本论文采用现场测量与数值模拟相结合的方法，讨论水泥包装车间转载点粉尘运动与分布规律，并在研究的基础上提出了转载点处粉尘治理方法。 以陕西某水泥包装车间为例，通过分析水泥粉尘的受力情况，结合现场测定的尘源性质和车间环境参数，建立了包装车间物理模型，运用计算流体力学软件FLUENT，得出了包装车间转载点处粉尘运动与分布规律，发现皮带机头附近工作区粉尘浓度超标。模拟结果与测点处测定结果基本一致，验证了模型的可靠性。 根据模拟结果，发现气流组织不合理和尘源的移动性是车间内粉尘浓度超标的主要原因。本文在保持原有除尘系统的条件下，将半封闭式车间改为封闭车间并建立了两种气流组织形式，模拟不同气流组织形式下车间内流场与粉尘浓度分布情况，并比较两者的控尘效果。结果表明，同侧上送下回比异侧上送下回有更好的控尘效果。同侧上送下回不仅可以稀释车间内粉尘，而且可以将大部分粉尘排出车间，而异侧上送下回仅能起稀释作用，粉尘运动杂乱无章。此外，分别分析了同侧上送下回气流组织形式下不同送风风速与排风口位置条件对粉尘运动与分布的影响，确定了最佳送风风速与排风口位置，即当送风风速在2m/s-2.5m/s，排风口高度低于皮带高度时控尘效果最好。

Being one of the major sources of atmospheric dust in our country, the annual dust emission raised by the cement industry accounts for about 40% the country's industrial dust emission a year. As the state has more and more strictly regulated the dust emissions from the cement industry with consistent efforts, the production and dust removal technology in the cement industry has gained substantial progress. The application of dust control technology so far, however, mainly focuses on raw material preparation, clinker burning and cement packaging,with less attention paid to cement transportation, especially to the dust generated at dust reproducing points. A cement packing plant in Xi'an is taken as the study site of the thesis. Dust distribution field, the characteristics of dust producing sources and the environment parameters in the workshop are analyzed to set up a reasonably simplified physical model. Computational fluid dynamics software FLUENT is used to simulate dust movement and distribution. It is found that dust concentrations around the transfer site exceed the standard limitation for the workspace. The simulation results fit the measured values nicely, thus the reliability of the model is verified. By scrutinizing the simulation results, it is found that the main reason of the unexpectedly high concentrations of dust lies in an undesirable pattern of air flow distribution and mobility of the dust producing source. In the current study with the existing dedusting system maintained, the model of semi-closed workshop is replaced by a closed shop model, and two kinds of air flow arrangement are established to simulate the flow field and the relevant dust concentration distribution in the shop in order to judge the respective effectiveness of dust control. The results show that the dust level with air outlets on the same side of the transfer conveyor is better than the one with the outlets on the opposite side of the conveyor. When the outlets are on the same side of the transfer conveyor, it can not only dilute the local dust, but can also discharge most of the dust outside. While the outlets are on the opposite side, only the dilution effect can be observed. In addition, calculations are performed to simulate the cases for outlets on the same side with different air speeds and outlet locations, leading to the best air velocity and vent locations for the optimum dust control, i.e the air speed of 2m/s-2.5m/s and the location of air vents below the height of the conveyor belt. This study reveals that the transformation of a semi-closed workshop into a closed one with a combined usage of overall ventilation and specific ventilation can effectively resolve the dust problem at dust reproducing locations in the cement packing plant and improve working environment.