Size-Resolved Density Measurements of Particle Emissions from an Advanced Combustion Diesel Engine: Effect of Aggregate Morphology

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• 作者：Teresa L. Barone ; Anshuman A. Lall ; John M. E. Storey ; George W. Mulholland ; Vitaly Y. Prikhodko ; Jennifer H. Frankland ; James E. Parks ; Michael R. Zachariah
• 刊名：Energy & Fuels
• 出版年：2011
• 出版时间：May 19, 2011
• 年：2011
• 卷：25
• 期：5
• 页码：1978-1988
• 全文大小：1038K
• 年卷期：v.25,no.5(May 19, 2011)
• ISSN：1520-5029

文摘

We report the first in situ size-resolved density measurements of particles produced by premixed charge compression ignition (PCCI) combustion and compare these with conventional diesel exhaust particles. The effective densities (蟻_eff) of size-classified particles were determined by measurements with a differential mobility analyzer (DMA) and an aerosol particle mass analyzer (APM). Particle inherent densities (蟻_i) were calculated using an expression for particle mass given by idealized aggregate (IA) theory, transmission electron microscopy (TEM) measurements of primary particle diameter (d_pp), and a comparison of the measured number of particles in each size class with that predicted by a proposed DMA-APM response function for aggregates. The 蟻_eff of PCCI and conventional diesel particles were similar over a range of diameters characteristic of their number-size distributions. The 蟻_eff were 0.89, 0.58, and 0.51 g/cm³ for conventional diesel and 0.90, 0.62, and 0.42 g/cm³ for PCCI particles with 50, 100, and 150 nm electrical mobility diameters (d_m), respectively. The error associated with 蟻_eff was about one percent of each measurement. The lowest 蟻_eff were observed for exhaust gas recirculation (EGR) levels somewhat lower than that required for PCCI operation. The 蟻_i of 50 and 100 nm conventional diesel particles were 1.22 卤 0.14 and 1.77 卤 0.29 g/cm³, which is in good agreement with previously reported values. PCCI 蟻_i for these size classes did not differ significantly (1.27 卤 0.16 and 2.10 卤 0.20 g/cm³), suggesting like amounts of adsorbed liquid hydrocarbons. In addition, for 150 nm particles, the PCCI and conventional 蟻_i were the same (2.20 卤 0.34 g/cm³). Given the close density values, we expect that particulate emissions control with diesel particulate filters (DPFs) would not be adversely affected by PCCI particle physical properties.