Effect of Air Movement to Spray Development of Rapeseed Oil in Diesel Engine

Fuel-air mixing is important process in diesel combustion. Generally there a two air mixing strategy, which is slow fuel - fast air mixing and fast fuel - slow air mixing. Air movement inside the combustion chamber greatly affect the mixing process and made effective fuel air mixing possible. Biomass fuel needs great help of mixing to atomization because the fuel has high viscosity and high distillation temperature. This study investigates the effect of air movement to spray development and atomization characteristics of rapeseed oil (RO). Optical observation of RO spray was carried out using shadowgraph photography technique and also using high speed camera. The results show that fast air movement effectively promotes RO spray atomization, with the RO spray expand outward from the main body through the whole spray length, which suggests fuel dispersion due to fast air movement.