Experimental investigation on charging characteristics and size distribution of diesel particles enhanced by corona discharge

Abstract

In this study, a wire-cylinder discharge reactor was used to charge the diesel particle. The effect of working parameters on charge-mass-ratio of diesel particles were experimentally investigated. The results show that the charge-mass-ratio of diesel particles increases by 137% as the negative discharge voltage increases from 4 to 16 kV. Compared to discharge voltage, the internal temperature only has a slight impact and the highest increase amplitude of charge-mass-ratio of diesel particles is 16% with the increment of internal temperature. In addition, material with high conductivity is a better choice for the discharge electrode and a smaller electrode diameter favours the increase of charge-mass-ratio. Furthermore, the particle size distribution at different discharge voltage was measured by an engine exhaust particle spectrometer (EEPS-3090) to evaluate the influence of discharge voltage on particle number emission. The results of EEPS indicate that corona discharge benefits the decrease of total particle number and nucleation mode particle number owing to the agglomeration of charged diesel particles, and the accumulation mode particle is less sensitive to the discharge voltage. Furthermore, the percentage of nucleation mode particle decreases from 67.7 to 56.7% as the voltage increases from 0 to 16 kV.

Keywords:

• Diesel engine
• particulate matter
• corona discharge
• charge-mass-ratio
• particle size distribution

Acknowledgements

We would like to acknowledge the financial support from the Natural Science Major Research Project of Jiangsu Province University (14KJA470001), the State Key Laboratory of Engines, Tianjin University (K2016-05), Natural Science Foundation of Jiangsu Province, China (BK20160538) and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).