| Abstract
| - The aim of this work is to investigate the effect of cavitation on the fuel flow and atomization characteristics of the biodiesel fuel. To study these characteristics of biodiesel as an alternative fuel, two different nozzles which have different length-to-width ratios were utilized in this experiment. The visualization system visualized the internal and external flow for investigating the formation and development of cavitation inside the orifice, and the internal flow characteristics were analyzed quantitatively using dimensionless numbers such as the Reynolds number, Weber number, cavitation number, and discharge coefficient. Moreover, the droplet measuring system was installed to study the effect of the formed cavitation on the fuel atomization such as the mean droplet size and the axial and radial mean velocity. On the basis of the results of the cavitating experiment, it was revealed that the mean droplet size of biodiesel is larger than that of diesel fuel. The droplet size became small when it formed the cavitation inside the orifice, and in the case of the high L/W ratio nozzle, the droplet size is also smaller than that of the low L/W ratio nozzle. From these results, it can be concluded that cavitation promotes the atomization of fuels at the nozzle exit. Also, it can be concluded from the results of flow characteristics that the cavitation formed along the nozzle orifice wall because of the change in the flow direction and the flow velocity near the wall due to the geometry of the orifice inlet.
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