Atomization and Sprays, Vol.31, No.7, 49-72, 2021
OPTICAL FUEL SPRAY CHARACTERIZATION OF HYDROTREATED VEGETABLE OIL, EN590 DIESEL, AND ETHANOL
The present study investigates hydrotreated vegetable oil (HVO), EN590 diesel, and ethanol sprays in terms of overall spray geometry and droplet sizes based on shadow image analysis. A solenoid driven multi-orifice heavy-duty size injector was used to inject fuels at varying conditions into a constant volume spray chamber filled with nitrogen at room temperature. The selected injection pressure range was between 600 and 2000 bar, and the chamber density was varied between 20 and 40 kg/m(3). The results showed that ethanol sprays have a wider spray opening angle and slower penetration rate compared to HVO and EN590 diesel. In general, spray tip penetration increased with an increase in injection pressure and decreased with an increase in chamber density. The spray opening angle increased by increasing the chamber density for all the fuels. The spray penetration results for HVO and EN590 diesel sprays were very similar to each other; however, HVO showed a wider spray opening angle than EN590 diesel at low injection pressure and low chamber density conditions. Ethanol sprays showed the largest opening angles compared to the rest of the fuels. The results concerning droplet size measurements suggested that the droplet sizes for all the tested fuels decrease by increasing the injection pressure. The droplet size values for HVO and EN590 diesel were very close to each other; however, ethanol sprays were characterized by smaller droplet sizes. The results also indicated larger droplet sizes at increased chamber density.
Keywords:alternative fuels;hydrotreated vegetable oil (HVO);ethanol;spray geometry;spray tip penetration;spray opening angle;droplet size;image analysis;shadow imaging