Study On Spray Characteristics Of Emulsified Diesel In Constant Volume Bomb

With the development of the economic, the total ownership of car continues to increase, and the pollution problem caused by automobile is becoming serious. The NOx and the soot and the other fine particles come from the exhaust pipes are considered to be the chief reason for the pollution of urban environment. There are many disadvantages of conventional fossil fuels, although many efforts were taken to improve the combustion performance, we still need to start from the source to have a deep research on the alternative fuel.Spray process is an important part of the combustion engine working process. The performance of spray characteristic have a direct impact on the formation of the gas mixture, and it will have a greatly influence on the subsequent combustion process and thereby affect the dynamic property, economic efficiency and emission performance. In this paper, simulation method was taken to study the spray characteristics of the emulsified diesel.By simulation, we used the three-dimensional numerical simulation software AVL’s FIRE to get the spray characteristics. We compared these results with the experiments, and verified the accuracy of the model. By changing the proportion of the water in emulsified diesel, we got understand of the spray characteristics change with the fuel which varies from the conventional diesel to the emulsified diesel. Also, we studied the influence of the fuel characteristics, injection conditions and environmental conditions on spray.The results showed that:Compared with the conventional fuel, emulsified diesel spray caused the lower temperature in the constant volume bombs. This will reduce the NOx emission in the combustion process. Also, because of the evaporation process, the oxygen concentration increased and the diesel vapor concentration decreased. This leads to the soot reduction in the cylinder. So, the emulsified diesel has better spray characteristics. For an emulsified diesel fuel contained with10%water, we can get a better spray results by raise the fuel temperature, environment temperature and injection pressure.