关键词: 自激振荡脉冲喷嘴, 空化效应, 射流形态, 空化泡, 雾化

Abstract: Based on the cavitation effects of the self-excited oscillation pulsed nozzles and multi-phase flow model, a cavitation model of the self-excited oscillation pulsed jets was established. The axisymmetric physical model of the chamber was built according to the self-excited oscillation chamber structures and its geometric parameters. The breakup of cavitation bubbles, two-phase distributions in the chambers, turbulent kinetic energy distributions and velocity distributions in an oscillation period of 100ms were obtained by numerical calculations. The results show that: in 1.02-2.37ms, the radii of cavitation bubbles decrease rapidly and the bubbles begin to do radial motions to form the accelerating jet on the bubbles surface. In 2.69-4.67ms, the bubbles start to crush when the pressures of cavitation bubble surfaces reach the limit breaking value. In the beginning of 25ms, the strong turbulent kinetic energy is formed at the contact interface between the main jet and air, and the center vortex area in self-excited oscillation chamber gradually grows up. Continuous jet in the outflow field is cut into the multiple jet and the jet velocity reaches a stable value about 30-40m/s near the axis of injection. In 40-90ms, the central cavitation airbag in the chamber has been formed and begins to block the movements of main jet, and the large cavitation area appears in the nozzle's outlet channel and the maximum turbulent kinetic energy is concentrated in the downstream of the lower nozzle exits. In the later period of oscillation, the velocity of main jet tends to be stable and the diffusion effects are weakened as the main jet interacts with the air and the penetration distances of the jet increase.

Key words: self-excited oscillation pulse nozzle, cavitation effect, jet form, cavitation bubble, atomization