標題: Collection efficiency and interstage loss of nanoparticles in micro-orifice-based cascade impactors
作者: Liu, Chun-Nan
Awasthi, Amit
Hung, Yi-Hung
Tsai, Chuen-Jinn
環境工程研究所
Institute of Environmental Engineering
關鍵字: Nanoparticle;Cascade impactor;Particle loss
公開日期: 1-四月-2013
摘要: In this study, two micro-orifice-based cascade impactors, including the micro-orifice uniform deposit impactor (MOUDI, MSP Model 110) and the NCTU micro-orifice cascade impactor (NMCI), were tested for the collection efficiency and interstage loss of nanoparticles. In the NMCI, new nozzle plates with smooth nozzle shape made by the LIGA (Lithography, Electroplating, and Molding) process were used to replace the 7th-10th stages in one of the MOUDI. Test results show that after adjusting proper S/W ratios (S: jet to plate distance, W: nozzle diameter) to 2.52, 3.01, 13.44, and 24.75 for the 7th, 8th, 9th and 10th stage of the NMCI, respectively, and 5.56, 11.18, 9.3, and 10.9 for the 7th, 8th, 9th and 10th stage of the MOUDI, respectively, the cutoff aerodynamic diameters (d(pa50)) are close to the nominal values given in Marple et al. (1991). Different S/W ratios are needed due to differences in the nozzle shape and nozzle diameter between two cascade impactors. Total interstage loss of nanoparticles from the inlet to the 6th-10th stage of the MOUDI exists due to the convection-diffusion mechanism, which increases with decreasing d(pa). For the MOUDI, total loss is 2.9-15.3 % (d(pa): 105.8 to 15.4 nm) for the inlet to the 6th stage and it increases to 20.1-26.1 % (d(pa): 23 to 15.4 nm) for the inlet to the 10th stage, respectively. Similar but slightly lower loss also exists in the NMCI. Field comparison tests in the ambient air show that mass size distributions measured by the MOUDI agree well with those of the NMCI. Finally, nozzle clogging tests using high concentration incense smokes indicate that the NMCI has a much less tendency for particles to clog in the nozzles than the MODUI. (C) 2012 Elsevier Ltd. All rights reserved.
URI: http://dx.doi.org/10.1016/j.atmosenv.2012.12.003
http://hdl.handle.net/11536/21357
ISSN: 1352-2310
DOI: 10.1016/j.atmosenv.2012.12.003
期刊: ATMOSPHERIC ENVIRONMENT
Volume: 69
Issue: 
起始頁: 325
結束頁: 333
顯示於類別:期刊論文


文件中的檔案:

  1. 000315932800035.pdf