表面处理车间槽边排风罩控制效果研究

发布时间：2018-01-30 11:34

本文关键词： 表面处理槽边排风污染物数值模拟控制风速风量计算　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着表面处理技术的迅速发展,在表面处理过程中所散发的污染气体种类也随之增多,同时工艺槽型式及尺寸也变得更加多样化以及控制标准的提高,采用何种局部排风形式以及多大的排风量才能有效控制表面处理车间工艺槽所散发的各种污染气体已成为目前该车间通风设计的关键。尽管对于不同局部排风形式的排风量计算方法国内外已有多种,但这些计算方法是否依然适用于各种工艺槽型式,需要加以验证。鉴于此,本课题研究在达到相同污染物控制效果要求时,表面处理车间中的槽边排风罩型式,工艺槽尺寸以及槽内溶液性质对槽边排风量的影响,并与现有的设计计算方法进行对比分析。首先,本课题采用实验的方法,针对单侧条缝式槽边排风罩研究了在不同的条缝风口风速下,槽边所在平面一定区域内的空气速度场分布规律,最终得到了一个关于风口风速、风口高度与槽边所在平面处各点速度的函数关系式。此外,本课题还通过实验的方法对盐酸溶液的蒸发速率理论计算公式进行了验证,实验结果与理论公式所得结果具有较好的吻合性。其次,本课题采用数值模拟的方法,首先分别针对不同污染物溶液性质确定了三档控制风速值即0.2m/s、0.25m/s和0.3m/s;然后分析研究了在达到相同污染物控制效果要求时,槽边排风罩型式、控制风速、槽宽以及槽长对排风量的影响并将各影响因素进行耦合后得到排风量的计算公式,结果表明:(1)在相同的排风罩型式、槽长及控制风速下,当控制区污染物浓度达到卫生标准要求时,排风量与槽宽近似成线性关系;(2)控制风速越大,排风量随槽宽的增长率也越大;(3)针对单侧条缝式排风罩,当槽宽超过700mm时,排风量随槽宽的增长率变大;(4)同种槽子,在满足卫生条件污染物浓度要求时,双侧条缝总排风量比单侧条缝风量减少50%以上。最后,通过对比本课题所得风量计算值与手册计算值发现,当控制风速分别为0.2m/s、0.25m/s和0.3m/s时,对于单侧槽边排风,当槽宽小于0.6m时,手册计算值偏大,槽宽大于0.6m时,手册计算值偏小;对于双侧槽边排风,在槽宽1.6m处出现同样的规律。
[Abstract]:With the rapid development of surface treatment technology, the types of polluted gases emitted in the process of surface treatment are also increasing, at the same time, the types and sizes of process tanks become more diversified and the control standards are improved. The key to the ventilation design of the workshop is which local exhaust air form and how much exhaust air quantity can be used to effectively control all kinds of polluted gases emitted by the surface treatment workshop process slot, although for different local exhaust air forms, it is the key to the ventilation design of the workshop at present. There are many methods for calculating the exhaust air volume at home and abroad. However, whether these calculation methods are still applicable to all kinds of process tank types need to be verified. In view of this, this paper studies the air cover type of groove side in the surface treatment workshop when the same pollutant control effect is achieved. The effect of the size of the process tank and the properties of the solution in the tank on the air flow rate of the tank side is analyzed and compared with the existing design and calculation methods. Firstly, the experimental method is adopted in this paper. The distribution law of the air velocity field in a certain area of the plane of the slot edge is studied under the different wind speed of the slit tuyere, and a wind speed about the tuyere is obtained. The relationship between the height of tuyere and the velocity of every point in the plane of the edge of the groove. In addition, the theoretical formula of evaporation rate of hydrochloric acid solution is verified by the experimental method. The experimental results are in good agreement with the theoretical results. Secondly, the method of numerical simulation is used in this paper. Firstly, according to the properties of different pollutant solutions, the third controlled wind speed is determined, that is, 0.2m / s 0.25m / s and 0.3m / s respectively. Then, when the same pollutant control effect is achieved, the type of the groove exhaust hood and the control wind speed are analyzed and studied. The influence of slot width and slot length on the exhaust air flow is analyzed and the calculation formula of the exhaust air flow rate is obtained by coupling the factors. The results show that the proportion of the exhaust air volume is the same under the same type of exhaust hood, slot length and controlled wind speed. When the concentration of pollutants in the control area reaches the hygienic standard, the relationship between the exhaust air volume and the slot width is approximately linear. (2) the larger the control wind speed, the greater the increase rate of exhaust air flow with the width of the slot; (3) when the width of the groove exceeds 700mm, the volume of exhaust air increases with the increase of the width of the slot. (4) for the same slot, when the concentration of pollutants in the sanitary condition was satisfied, the total air output of the bilateral slit was more than 50% less than that of the one side slot. Finally. By comparing the calculated values of air volume with those of the manual, it is found that when the controlled wind speed is 0.2m / s / s 0.25m / s and 0.3m / s, respectively, the outlet air is on one side of the slot. When the slot width is less than 0.6 m, the calculation value of the manual is larger, and when the slot width is larger than 0.6 m, the calculation value of the manual is small. For both sides, the same rule appears at the width of 1.6 m.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU834

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