Property of Cavitation Cloud Shedding in an Orifice Nozzle

• Published in: 2023 9th International Conference on Fluid Power and Mechatronics (FPM) pp. 1 - 6
• Main Authors: Peng, Guoyi, Takakura, Kaishu, Li, Kaizheng, Onishi, Taihei, Oguma, Yasuyuki
• Format: Conference Proceeding
• Language: English
• Published: IEEE 18.08.2023
• Subjects: bubble cloud; Cameras; Cavitation; Employee welfare; flow visualization; Fluids; LIF-PIV; Mechatronics; Numerical simulation; orifice nozzle; Orifices; Visualization
• DOI: 10.1109/FPM57590.2023.10565428

Concerning the unsteady cavitation phenomenon occurring in an orifice nozzle under submerged condition, the property of cavitation cloud shedding is investigated by combined utilization of flow visualization methods. The pattern of cavity releasing is evaluated by analyzing a sequence images of high-speed camera, and the velocity distribution is evaluated by LIF-PIV under the same working condition. The mechanism of cavity formation and release is further examined by comparing the results of flow visualization and numerical simulation. The result reveal that one pair of ring-like clouds consisting of a leading cloud and a subsequent cloud is successively shed downstream, and this process is periodically repeated. The leading cloud is principally split by shear flow, and the subsequent cloud is detached by the re-entrant jet generated while a fully extended cavity breaks up. The subsequent cavitation cloud catches the leading one and they coalesce over the range of x/d ≈ 1.8~2.5. Two dominant frequencies of cavitation cloud shedding are estimated to be f1 = 1403 Hz and f2 = 2791 Hz. The mass flow rate coefficient fluctuates periodically corresponding to the first dominant frequency of cloud shedding, and the average equals approximately 0.63.