Proceedings of the
International Conference on Mechanical Engineering 2009
(ICME2009) 26- 28 December 2009, Dhaka, Bangladesh

ICME09-TH- 28

MORPHOLOGICAL STUDY OF THE PARTICULATE MATTER
SAMPLED FROM THE EXHAUST OF A DIESEL ENGINE IN
DIESEL AND DUAL FUEL MODES

Nirendra N Mustafi1, Robert R Raine2
1Dept. of Mechanical Engineering, Rajshahi University of Engg. and Tech., Rajshahi, Bangladesh
2Dept. of Mechanical Engineering, The University of Auckland, Auckland, New Zealand

ABSTRACT

The particulate matter (PM) of a diesel engine operated on diesel and dual fuel modes are sampled and characterized by size, morphology and fractal geometry by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The gaseous fuels used are natural gas and synthetic biogas. The engine operating condition is kept the same to compare the results between diesel and dual fuel PM. SEM images yield PM agglomerate number size distributions and a shape description. TEM images provide the primary particles size distribution in PM agglomerates and the fractal dimensions. Long chainlike PM agglomerates appear for the diesel PM, whereas those for dual fueling are found to be smaller and rounder. All of the measured PM appear to have a bi-modal number size distribution. The average primary particle diameter increases for dual fuel PM (ranging from 26.9 to 29.5 nm) compared to diesel PM (26.4 nm). The average primary particle diameter tends to increase for biogas fueling. Higher fractal dimensions (from 1.73 to 1.88) are obtained for dual fuel PM compared to diesel PM (1.69) implying that diesel PM are more chainlike and elongated. Based on the obtained results, a conceptual model is constructed to understand the phenomena of PM formation for the two types of engine fueling.

Keywords: Dual Fuel Engine, Particulate Matter, Morphology.

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