Three dimensional modeling of the effects of different spray angles and number holes on the combustion process and emission formation in a direct injection diesel engine

This study presents a computational study of mixture formation, flame front movement, combustion process and emission formation at the various spray angles and number holes in a direct injection diesel engine. This work is carried out in a direct injection OM355 diesel engine at four and five holes with 130°, 135° and 140° spray angles. The amount of fuel injected per cycle is constant at all states. The results of the model show that with an increasing spray angle, the combustion parameters such as heat release rate, in cylinder pressure and temperature because of more spray impinging decrease while with an increasing number of holes, a slight variation take place at these parameters. From emission formation point of view, with an increase in spray angle, NOx decreases and soot increases. Also with an increase in the number of holes, the similar trends are observed. The results of model for baseline engine are good agreement with the corresponding experimental data. In other cases, the results are in good agreement with the corresponding data in the literature.