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| Experimental study on cavitation cloud evolution law of cavitation jet of convergent-divergent nozzle |
| LI Wei1*, ZHANG Wenquan1, SHI Weidong2, YANG Yongfei1, CAO Weidong1 |
| 1. National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2. College of Mechanical Engineering, Nantong University, Nantong, Jiangsu 226019, China |
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Abstract To reveal the characteristics of cavitation jet flow field under different pump pressures and analyze the effect of inlet pressure on the evolvement law of cavitation could, an experiment on high-pressure cavitation jet of convergent-divergent nozzle was carried out by means of high-speed photography. The results show that the cavitation cloud of the submerged cavitation jet evolves periodically, which contains four stages in one cycle, namely initiation, development, shedding and collapse. The area, concentration and width of the cavity reach the highest values at the moment of shedding. With the increase of the pressure, the velocity of the jet center increases and velocity gradient in jet boundary la-yer increases, which intensifies the shearing action between the high-velocity flow and the steady li-quid, and thus leads to the increase of the cavitation dimension. Meanwhile, With the increase of the pressure, the shearing process leads to increasing turbulent kinetic energy, the contour profile of the cavitation cloud becomes vague, which increases the shedding frequency of the cavity. The results provide theoretical significance and guidance value for application of cavitation jet in the field of metal surface treatment, petroleum drilling and rock breaking.
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Received: 07 January 2019
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