標題: Design and Testing of the NCTU Micro-Orifice Cascade Impactor (NMCI) for the Measurement of Nanoparticle Size Distributions
作者: Chien, Chih-Liang
Tien, Chi-Yu
Liu, Chun-Nan
Ye, Huajun
Huang, Wei
Tsai, Chuen-Jinn
環境工程研究所
Institute of Environmental Engineering
公開日期: 1-一月-2015
摘要: The NCTU micro-orifice cascade impactor (NMCI) was redesigned and tested to enable the measurement and adjustment of the jet-to-plate distance (S) of the impactors by using a micrometer. Each stage of the NMCI contains an impaction plate and a nozzle plate which are separated. The bottom casing for impaction plate assembly and the nozzle plate holder of each stage are separated. Calibration results show that the cutoff aerodynamic diameter (d(pa50)) of the three lower stages (d(pa50) = 180, 100, and 56 nm) are close to the nominal values given in Marple et al. (1991). In addition, the S/W (W: nozzle diameter) effects on the d(pa50) for the three lower stages were investigated and an empirical equation was developed to facilitate the prediction of d(pa50) when the nozzle diameters may change slightly from one batch to another. The relationship between the nozzle diameter and pressure drop of the micro-orifice impactors at the fixed operational flow rate of 30 L/min was also established so that the nozzle diameters can be predicted from the pressure drop measurement. An empirical equation was proposed to express the correlation between the dimensionless cutoff size and the S/W ratio when considering isentropic flow to facilitate the design of microorifice impactors for S/W > 4. It is expected that the present NMCI could improve the accuracy of size classification of submicron particles below 180 nm, especially for nanoparticles.
URI: http://dx.doi.org/10.1080/02786826.2015.1089976
http://hdl.handle.net/11536/129438
ISSN: 0278-6826
DOI: 10.1080/02786826.2015.1089976
期刊: AEROSOL SCIENCE AND TECHNOLOGY
Volume: 49
Issue: 10
起始頁: 1009
結束頁: 1018
顯示於類別:期刊論文