固壁面附近激光产生空泡脉动过程的实验研究

采用自行研制的光纤传感器研究了激光等离子体空泡在固壁面附近的脉动特性。实验获得了激光空泡三次膨胀到最大位置对应的波形图;并据此判定了激光空泡在脉动过程中对应的最大泡半径和溃灭周期;在此基础上结合空泡溃灭理论,计算了激光泡溃灭周期的延长因子κ。结果表明:随着脉动次数的增加,最大泡半径依次减小;随着作用激光能量的增大,最大泡半径,空泡溃灭周期的延长因子κ均增大;而无量纲参量的增大将导致延长因子的减小。所得到的延长因子同样可用于无限域流场。

Experimental Investigation of the Oscillation of a Laser-Generated Cavitation Bubble Near a Solid Boundary

The oscillation of a laser-generated cavitation bubble near a solid boundary is investigated with a home-made optical fiber sensor. The oscillogram corresponding to that the radius of the cavitation bubble expands to the maximum for 3 times is experimentally studied, based on which the maximum bubble radius and the collapse time for each oscillation cycle are determined. By combining the collapse theory of the cavitation bubble, the prolongation factor κ of the collapse time is calculated. A dimensionless parameter γ is defined as L/Rmax, where Rmax is the maximum bubble radius and L is the distance from the cavity core to the boundary. The results show that, the maximum bubble radius decreases with the increase of the oscillation time, with the rise of the laser energy Rmax and κ increase, and the rise of γ minishes κ. The polongation factor κ derived above is also valid in the infinite liquid field.