There is no micro-explosion in the diesel engines fueled with emulsified fuel

Abstract

According to the criterion of micro-explosion occurrence, a new viewpoint that micro-explosion may not occur in diesel engines is presented in this paper. The relationship among the diameter change of an emulsified fuel droplet, water and fuel evaporation rate is obtained from the multi-component control equations of the droplets. Because the evaporation rate of water is much more rapid than that of fuel, water will evaporate much quickly than fuel in this process, so the water is evaporated in advance, and at the same time large droplets change into small ones. This is in fact the main reason of combustion intensification for emulsified fuel. The investigators at home should notice that the fuel droplets used in the previous experiments were always droplets with big diameter (about d 0 ≥250 μm), which might be owing to the restriction of the experimental conditions. Micro-explosion does happen on such fuel droplets with big diameters, which has caused all the authors to think that micro-explosion would happen on all the droplets without exception. However, it cannot be used to explain what really happens in diesel engines. In our research, we have found that micro-explosion will not occur when the size of droplets is too small, and the same is case with diesel engines.

Current Trends in Water-in-Diesel Emulsion as a Fuel

“…The advantages on performance and emissions of water-in-diesel fuel and factors affecting microexplosion have been extensively researched. Fu [ 68 ] and coworkers have challenged its occurrence inside diesel engine combustion chamber. Based on their conclusion, the droplet diameter of an emulsion in the combustion chamber is in the range of 20–30 μ m and microexplosion phenomenon could not occur with this range of droplet sizes [ 38 ].…”

Micro-explosion of a water-in-hexadecane compound drop

“…According to Fu et al (2006), the micro-explosion would not occur if the drop size was too small. The outer diameter of the compound drop in this study was so large that the micro-explosion was possible.…”

Emulsification of animal fats and vegetable oils for their use as a diesel engine fuel: An overview

“…The microexplosion is also questioned [91]. Califano et al [75] pointed out that the microexplosion does not always occur, and that its occurrence depends on a number of parameters.…”