Physical Size Distribution Characterization of Diesel Particulate Matter and the Study of the Coagulation Process 780788
Diesel particulate matter in both the diluted and undiluted state is subject to the processes of coagulation, condensation or evaporation, and nucleation which causes continuous changes in its physical characteristics. The Electrical Aerosol Analyzer (EAA) is used to measure the diesel particle size distribution in the MTU dilution tunnel for a naturally aspirated direct-injection diesel engine operated on the EPA 13 mode cycle.
The design and development of accurate and repeatable sampling methods using the EAA are presented. These methods involve both steady-state tunnel and bag measurements. The data indicate a bimodal nature within the 0.001 to 1 μm range.
The first mode termed the “embroynic mode” has a saddle point between 0.005 to 0.015 μm and the second mode termed the “aggregation mode” lies between .08 to .15 μm for the number distribution. The particle concentration decreases with time and the resulting size distribution function approaches an asymptotic steady-state solution indicating the self-preserving nature of particulate size distributions. Coagulation constants have been calculated for the diesel particles and are compared to theoretical values in the literature.
Citation: Khatri, N. and Johnson, J., "Physical Size Distribution Characterization of Diesel Particulate Matter and the Study of the Coagulation Process," SAE Technical Paper 780788, 1978, https://doi.org/10.4271/780788. Download Citation
N. J. Khatri, John H. Johnson
Michigan Technological Univ.
1978 SAE International Off-Highway and Powerplant Congress and Exposition
The Measurement and Control of Diesel Particulate Emissions-PT-17, SAE 1978 Transactions-V87-A