工业厂房局部排风气流流场特性及逃逸粉尘控制策略研究

发布时间：2019-05-07 00:53

【摘要】：在化工、石油、冶金、电力等工业生产中，经常存在高温污染源，高温污染源会不断向环境中散发污染物，影响工作区环境质量。目前多采用局部排风系统对此部分污染物进行控制。但是由于在工业生产中，为满足工艺设计的要求、场地的限制、以及人工操作等诸多因素的影响，局部排风系统往往不能合理设置。污染物的控制效果并不理想，仍然有大量污染物逃逸到工作区，对工人工作环境造成影响。本文以此为背景，对局部排风系统作用下，污染物仍然大量逃逸问题进行研究，在对气流流场特性以及粒子分布的分析基础上，提出相应控制策略。首先，本文在确定了合理的湍流模型以及边界条件的基础上，，分析了造成逃逸现象的不同影响因素，分别为热射流初速度，热射流初始温度，热射流初速度方向与排风罩控制速度方向夹角，对这些因素设置不同的工况进行模拟计算，通过计算所得到的流场特性，分析局部排风罩处逃逸原因以及逃逸出的气流的流量特性。其次，在流场计算结果的基础上，利用DPM颗粒轨道离散模型，加载粒子相，数值模拟计算两相流，得到粒子运动轨迹，通过房间温度分布、粒子逃逸率以及逃逸粒子在空间分布情况来分析不同影响因素下，对房间环境造成的影响。最后，针对本文分析得出的影响逃逸的因素，提出相应的控制策略，如增大原排风罩风量、为原排风罩加设挡板以及增设二次排风罩，并且对几种控制策略的控制效果进行分析，为实际工业生产改进措施提供理论依据。
[Abstract]:In chemical, petroleum, metallurgy, electric power and other industrial production, there are often high-temperature pollution sources, high-temperature pollution sources will continuously release pollutants to the environment, affecting the environmental quality of the work area. At present, local exhaust air system is often used to control this part of pollutants. However, in order to meet the requirements of process design, the limitation of site, and the influence of many factors such as manual operation, the local air exhaust system can not be set up reasonably in industrial production. The control effect of pollutants is not ideal, there are still a large number of pollutants escape to the work area, which has an impact on the working environment of workers. In this paper, a large number of pollutants still escape under the action of local exhaust system are studied. Based on the analysis of the characteristics of air flow field and the distribution of particles, the corresponding control strategies are put forward. Firstly, on the basis of the reasonable turbulence model and boundary conditions, the different influencing factors of escape phenomenon are analyzed, which are the initial velocity of hot jet and the initial temperature of hot jet, respectively. The angle between the initial velocity direction of the heat jet and the control velocity direction of the exhaust hood is included. These factors are simulated under different working conditions, and the characteristics of the flow field obtained by the calculation are calculated. The reasons of escape and the flow characteristics of the escaped air flow are analyzed. Secondly, on the basis of the results of the flow field calculation, the particle trajectory is obtained by using the discrete model of the DPM particle orbit, loading the particle phase, and numerically simulating the two-phase flow, and the temperature distribution in the room is obtained. The effects of different factors on the room environment are analyzed by means of the particle escape rate and the spatial distribution of the escape particles. Finally, in view of the factors that affect the escape, the corresponding control strategies are put forward, such as increasing the air volume of the original exhaust hood, setting up the baffle for the original exhaust hood and adding the secondary exhaust cover. The control effects of several control strategies are analyzed in order to provide the theoretical basis for the practical industrial production improvement measures.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：X962;X701.2

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