高效空气过滤器的流场一致性研究

发布时间：2018-05-27 06:31

本文选题：高效空气过滤器 + 气流分布一致性　；参考：《东华大学》2013年硕士论文

【摘要】：高效空气过滤器(HEPA)作为洁净技术行业的核心设备,其效率的提升、性能的优化对与其相关行业的发展有着重大的意义。近年来其发展引起了诸多国家的重视,低阻高效成了空气过滤器发展共同的主题。鉴于新型滤材的高昂价格及低碳环保的要求,合理、充分利用滤料,提高其整体使用寿命显得非常必要。目前,HEPA多存在以下两个方面的瑕疵：因均流板设计不合理引起的迎风面入口流量分布不均匀的现象,从而导致滤料得不到最优化的利用；过滤器检漏发尘方式的不合理,使得气溶胶大量残留对过滤器寿命造成挑战,同时存在目标气溶胶时间不一致性和污染环境的潜在可能。本课题将基于目前已经广泛使用的数值模拟计算技术,对上述两个问题展开分析。本文的基本思路是：立足于相应的假设和简化,借助CAD进行过滤器三维建模,采用GAMBIT进行网格处理,最终通过FLUENT软件进行数值计算。为验证数值模拟方式中模型的合理性、边界条件选取的准确性,本文还开展了相应的对照试验,并通过试验与模拟的对比最终确定了数值模拟过程中：湍流模型采用标准κ-ε模型、滤料采用多孔介质模型及速度入口、压力出口边界定义的合理性。对于无隔板高效空气过滤器,在静压箱尺寸一定的情况下,过滤器入口流速分布的一致性主要受均流板影响,而均流板的几何结构、几何尺寸、安装高度、开孔孔径、孔间距等都在不同程度上影响着均流板的性能。本文对均流板性能的主要影响因素：大小、开孔率、安装高,用正交试验法进行模拟实验设计,建立不同过滤器物理模型,对常用的2000m3/h、1500m3/h、1000m3/h及500m3/h过滤器模型分别开展了试验研究。对于过滤器检漏中的气溶胶发生方式,本文先开展了不同“点源”发尘的实验研究,验证了多点发尘有利于缩短混合距离；继而进行了不同数目点源、相对于气流流向的顺流、逆流、垂直流三种发尘方向的多组模拟试验研究。模型等的建立、处理沿袭了速度分布一致性的相方法。本课题采用速度(浓度)分布的相对误差和不均匀度作为评价指标。结果表明：对于不同的过滤器模型,均流板的设计应有不同的方式,不能单独依照经验。对于2000m3/h过滤器模型,其入口气流的一致性主要受均流板大小影响,最优安装高度为50mm,而其余三种风量模型入口气流一致性主要由均流板开孔率决定。对于气溶胶的混合,当发尘“点源”的数目足够多时,在有限的静压空间内是能够混合均匀的,当然有扰流的情况下更能够加速气溶胶的混合均匀。
[Abstract]:As the core equipment of clean technology industry, HEPA (High efficiency Air filter) is of great significance to the development of related industries with the improvement of its efficiency and the optimization of its performance. In recent years, its development has attracted the attention of many countries, low resistance and high efficiency has become the common theme of air filter development. In view of the high price of new filter material and the requirement of low carbon environmental protection, it is very necessary to make full use of filter material and improve its whole service life. At present, HEPA has the following two defects: the phenomenon that the inlet flow distribution is not uniform due to the unreasonable design of the uniform flow plate, which leads to the unoptimized utilization of the filter material, and the unreasonable method of filter leakage dusting, A large amount of aerosol residues pose a challenge to the filter life, and there is a potential for target aerosol time inconsistency and environmental pollution. Based on the widely used numerical simulation techniques, the above two problems are analyzed in this paper. The basic idea of this paper is: based on the corresponding assumptions and simplification, the filter 3D modeling is carried out with the help of CAD, the mesh processing is done by GAMBIT, and the numerical calculation is carried out through FLUENT software. In order to verify the rationality of the model and the accuracy of the selection of boundary conditions in the numerical simulation mode, a corresponding comparative experiment was carried out in this paper. Through the comparison between the experiment and the simulation, the rationality of the definition of the boundary of the pressure outlet and the boundary of the pressure outlet is finally determined by comparing the results of the experiment and the simulation. For the high efficiency air filter without diaphragm, the uniformity of flow velocity distribution at the inlet of the filter is mainly affected by the uniform flow plate, and the geometric structure, geometric size, installation height, aperture of the orifice of the uniform flow plate, when the size of the static pressure box is fixed, is mainly affected by the flow sharing plate. The hole spacing affects the performance of the plate to some extent. In this paper, the main factors that affect the performance of the flow sharing plate, such as size, opening rate and high installation, are simulated and designed by orthogonal test method, and different filter physical models are established. The commonly used 2000m3 / 1 500m3 / h and 500m3/h filter models are tested and studied respectively. For the aerosol generation in filter leak detection, the experimental study of different "point source" dusts is carried out, which proves that multi-point dust emission is beneficial to shorten the mixing distance, and then different number of point sources, relative to the downstream flow of air flow, are carried out. A multi-group simulation study of three dusting directions for countercurrent and vertical flow. The establishment of the model deals with the phase method that follows the consistency of velocity distribution. The relative error and unevenness of velocity (concentration) distribution are used as evaluation indexes. The results show that the flow sharing plate should be designed in different ways for different filter models. For the 2000m3/h filter model, the consistency of inlet airflow is mainly affected by the size of the flow sharing plate, and the optimal installation height is 50mm, while the inlet airflow consistency of the other three air volume models is mainly determined by the orifice rate of the flow sharing plate. For aerosol mixing, when the number of dust "point sources" is large enough, it can be mixed uniformly in a limited static pressure space, and of course, it can accelerate the mixing uniformity of aerosol in the case of disturbing flow.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU834.83

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