EXPERIMENTAL STUDY OF PRIMARY ATOMIZATION IN TRIPLE CO-PLANAR AND NON-PLANAR IMPINGING JETS

In the present work, a comprehensive experimental study has been performed on the liquid sheet of triple converging orifice jets, in two configurations including planar and nonplanar. A large number of experiments have been done to observe the liquid sheets in a wide range of Reynolds numbers, from 1000 to 11,000, using the high-speed shadowgraph technique to capture the images in the spray domain. As an another remarkable merit of this study, an analytical solution has been presented which is able to calculate the triple planar jet liquid sheet thickness. In this research, the effects of injector diameter and jet velocity on the liquid sheet characteristics were investigated. The results indicated that the length and width of the triple jet liquid sheet as well as the number of droplets increased by raising the Reynolds number, while the mean diameter of droplets decreased meaningfully. The rise of Reynolds numbers also heightened the dispersion factor in the spray. A complete examination was done to compare the triple and double impinging jet liquid sheets with each other. Findings indicated that adding the third jet diminished the dispersion factor and number of droplets at the same Reynolds number. The analytical solution results suggested that the thickness of the liquid sheet was thicker in the triple coplanar jets than in the double jets, leading to the coarser spray in the triple jets. Finally, in another configuration of triple jets, the nonplanar one in which three cylindrical jets were not in a plane, the size of droplets was slightly greater than that of the spray of double jets, while smaller in comparison to the triple coplanar configuration.