Experimental study of the effect of n-butanol additive on spray characteristics of biodiesel in a high-pressure common-rail injection system
The aim of this study was to investigate the spray characteristics of biodiesel and n-butanol/biodiesel blended fuel. The spray tip penetration and the spray cone angle were tested and analyzed. A constant volume chamber and high-speed camera were used to observe the spray evolution and a common-rail system was employed to change the injection pressure. The results show that the spray tip penetration and the spray cone angle of biodiesel are larger than those of blended fuel in most cases. n-Butanol additive changes the relationship between angle and density ratio to a certain degree. The experimental trend lines support the penetration model proposed by Hiroyasu and Arai in terms of similar proportional relation on time after start of injection, and the empirical equations provide reasonable agreement with the experimental data of the spray tip penetration.