Hydraulic fip 발생 분사조건에 대한 실험 연구

• Published in: 한국분무공학회지, 30(3) pp. 162 - 171
• Main Authors: 은정우, 이현창
• Format: Journal Article
• Language: Korean
• Published: 한국분무공학회 01.09.2025
• Subjects: 기계공학
• ISSN: 1226-2277

Hydraulic flip occurs when a jet is discharged without reattaching to the orifice wall after separation at the inlet. This phenomenon can significantly alter spray characteristics that the injection conditions for hydraulic flip initiation need to be specified in order either to avoid or to induce the phenomenon, depending on the application. In this study, water jet was injected through sharp edged single orifice nozzle (d = 0.6mm, l/d = 6.1) at various Pinj, Tinj and Pch to experimentally determine the initiation criteria. The internal geometry of the injector was characterized by using optical microscope and white light interferometry and sharpness of the inlet edge has been confirmed. Three different injection cases have been investigated: ambient Tinj, high Tinj and low Pch. During each experiment, the relevant pressures, temperature, and mass flow rate were monitored along with synchronized backlight images. Hydraulic flip initiation was evaluated using both discharge coefficient analysis and image-based observation of the jet. The result of ambient Tinj case was in close agreement with those reported in the previous study. Furthermore, hydraulic flip was successfully realized and observed in high Tinj case, conditions under which it had not been extensively reported. The corresponding initiation thresholds for each case are proposed. These findings provide a more comprehensive understanding of hydraulic flip initiation and can serve as a design reference for injection systems where precise jet breakup control is required. KCI Citation Count: 0