1. Summary
of the physical parameters of four different types of fuels (gasoline, diesel fuel, HVO, FAME) and phenomena related to these parameters, which include the spraying of fuel drops and the coalescence and collision of these drops. The fuel drop sizes after leaving the injector and after mutual collisions were calculated.
The results can be summarized as follows:
  1. In the hybrid breakout model, spray velocity has a significant effect on the drop size. As the spray velocity increases, the size of drops decreases in the fuel spray. When considering the conditions under which fuel is sprayed in a working engine, then viscosity and surface tension are the factors that have a significant effect mostly at the low spraying velocities. The higher the velocity of fuel spray, the lower the effect of viscosity and surface tension have on the drop size in the fuel spray. According to the used model, the diameter of the injection opening does not have an effect on the drop size in the fuel spray.
  2. When biodiesel fuel is used, then according to the hybrid breakout model the drop size in the fuel spray is somewhat greater (~12%). As the fuel spray velocity increases, the size ratio of drop increases.
  3. When the drops collide in the fuel spray, then generally the drop size increases as the value of impact parameter B increases, if the drop size ratio of colliding drops is Δ  = 0.5. If the drop size ratio of colliding drops is Δ  = 1, then at the impact parameter’s value of = 0.1, the size of drops after breakout is the smallest. As the impact parameter B increases or decreases, the drop size in the fuel spray starts to increase. The physical and chemical properties of fuels do not have a significant effect on the drop size. Minor differences occur when drops of the same size collide at the impact parameter value range ofB  = 0.5–1.5.
  4. The biodiesel air-fuel mixture contains somewhat larger drops than the air-fuel mixture of diesel fuel. The results show that the model used in study cannot be used to account for the reduction of the soot level of biodiesel fuel. This is due to the fact that the quality of the biodiesel air-fuel mixture is not significantly different from diesel fuel.
There are several further questions that need to be addressed:
  1. How does the oxygen contained in the fuel influence the soot level of the combustion of the fuel?
  2. How do the fuel drop sizes change in the injection chamber for the four types of fuel (gasoline, diesel fuel, HVO, FAME) both temporally and spatially?
The topic of the article is related to the scope of the Journal of the Power and Technologies by the theme of renewable energy. The article provides an overview of the behavior of biofuels’ drops in the spray, what is more, it supplements the database of the journal with explanations of the problems of biofuels’ spray.   
  1. References