Evaluation of Optimal Water Content on an Emulsified Fuel Droplet for Diesel Engine 2019-32-0614
It is expected for emulsified fuel to improve performance(1) of Diesel engine as thermal efficiency and emissions. The advantage of emulsified fuel is to use secondary atomization. The secondary atomization occurs, because of difference of boiling point between fuel and water. The water content strongly influence on timing of secondary atomization. However, water content is determined empirically as ever. In previous report(2)(3), it has been reported an engineering evaluation of emulsified fuel to determine optimal water content. Namely, an emulsified fuel droplet is adopted Weibull pots as a statistical evaluation. The experimental data show optimal water content is extremely difference between diesel fuel and neat bio fuel. This paper focuses on the cause of this difference of optimal water content. About this point in this paper, the remarkable parameter is kinematic viscosity and ingredients in fuel. The 4 kind of test fuels are provided, 2.65[mP·s], 13.30[mP·s], 36.50[mP·s], 75.00[mP·s]. The experimental data show that optimal water content of low kinematic viscosity fuel converges toward a point at 23%, however, higher kinematic viscosity fuel change to wider range of optimal water content gradually. It is suggested that optimal water content of fuel droplet is influenced on internal motion of dispersed water. Moreover, it is investigated that effectiveness of ingredients in fuel on optimal water content. The tested fuels are sunflower oil and bean oil which aim at similar kinematic viscosity and different kind of fatty acid ingredients. The effectiveness of ingredients has been confirmed hardly in this research.