Experimental Study on Impinging Jet Atomization Using Doublet and Quadruplet Jets

The process of impinging-jet atomization involves the collision of multiple liquid jets to create atomization. This study specifically focuses on a system that utilizes impinging atomization with multiple jets. The injectors used in this study are arranged in either a planar configuration for doublet injectors or a stereoscopic configuration for quadruplet injectors, both designed to facilitate impinging atomization. The angle at which the jets collide is set at 90 degrees, with injector intersection angles of either 60 degrees or 120 degrees. The diameter of the jets ranges from 0.8 to 1.1 mm, while the length-diameter ratio of the pipe remains fixed at 10. To investigate the atomization process, experiments were conducted by varying flow rates (ranging from 30 to 130 mL/min) from each injector using pure water as the working fluid. This resulted in a range of Weber numbers spanning from 4 to 206 and Reynolds numbers ranging from 578 to 3443. Four atomization regimes were observed in the impinging atomization flow field: closed-rim mode, periodic drop mode, open rim mode, and fully developed mode. The experiment utilized a high-speed camera to observe the formation and breakup of the liquid sheet. However, increasing the number of jets and altering the impingement configuration had minimal impact on the liquid sheet patterns as the Weber number increased. Compared to traditional double jet atomization, quadruplet jet atomization resulted in the wider extension of liquid sheets and similar atomization patterns. This study is useful for designing jet impingement-atomization systems for confined spaces.