Kim Dong-Uk, Kim Jin-Tae, Jeong Sang Hyun, Lee Sang-Sup
Department of Environmental Engineering, Chungbuk National University, Cheongju, Republic of Korea.
Environmental System Research Division, Korea Institute of Machinery & Materials, Daejeon, Republic of Korea.
J Air Waste Manag Assoc. 2021 Mar;71(3):328-338. doi: 10.1080/10962247.2020.1808114. Epub 2020 Dec 22.
A wide-angle diffuser installed at the entrance of an electrostatic precipitator (ESP) causes a non-uniform flow distribution due to the boundary layer separation. Because a non-uniform flow pattern decreases the particulate matter control efficiency of an ESP, it is important to maintain a uniform flow distribution. The objective of this study is therefore to understand flow distribution with the conditions of perforated plates placed in the diffuser and then to design an ESP to obtain uniform flow. Discharge coefficients were determined varying the porosity, thickness, and number of holes of the perforated plate inside the lab-scale duct system. The test results suggest that the perforated plate with a porosity of 50%, a thickness of 5 mm, and 0.104 hole/m perforated plate is most acceptable. This perforated plate was placed in the diffuser of the lab-scale ESP system. Velocity profiles in the body of the ESP were obtained depending on the number and arrangement of perforated plates in the diffuser. One perforated plate placed in the diffuser did not improve the flow distribution. Although more uniform flow distribution was found with two perforated plates, stalled flow regions still existed at the top and bottom of the ESP body. When three perforated plates were placed in the diffuser, the 2nd and 3rd perforated plates were important to obtain uniform flow distribution. When the 2nd and 3rd perforated plates were placed at the inlet side and outlet of the diffuser, respectively, the most uniform flow distribution was obtained in the body of the ESP.: In order to determine the optimal perforated plate for Electrostatic Precipitator (ESP), we investigated the discharge coefficient depending on the structure of the perforated plate in a square duct. We measured the velocity distribution in a laboratory ESP with perforated plates and found the effect of the number and arrangement of perforated plates on the flow distribution in the collection region. Based on the test results, we found the configuration of perforated plates for uniform flow distribution in the body of the ESP.
安装在静电除尘器（ESP）入口处的广角扩散器会因边界层分离导致气流分布不均匀。由于不均匀的流型会降低ESP对颗粒物的控制效率，因此保持均匀的气流分布很重要。因此，本研究的目的是了解在扩散器中放置多孔板的情况下的气流分布，然后设计一种ESP以获得均匀的气流。在实验室规模的管道系统中，通过改变多孔板的孔隙率、厚度和孔数来确定流量系数。测试结果表明，孔隙率为50%、厚度为5毫米且孔密度为0.104个/米的多孔板是最可接受的。将该多孔板放置在实验室规模的ESP系统的扩散器中。根据扩散器中多孔板的数量和排列，获得了ESP主体内的速度分布。在扩散器中放置一块多孔板并不能改善气流分布。虽然两块多孔板的气流分布更均匀，但在ESP主体的顶部和底部仍存在滞流区域。当在扩散器中放置三块多孔板时，第二块和第三块多孔板对于获得均匀的气流分布很重要。当第二块和第三块多孔板分别放置在扩散器的入口侧和出口时，在ESP主体中获得了最均匀的气流分布。为了确定静电除尘器（ESP）的最佳多孔板，我们研究了方形管道中多孔板结构对流量系数的影响。我们测量了带有多孔板的实验室ESP中的速度分布，并发现了多孔板的数量和排列对收集区域气流分布的影响。基于测试结果，我们找到了使ESP主体内气流分布均匀的多孔板配置。
