The Dynamic Process And Cavitation Luminescence Of Transient Single Acoustic Cavitation Bubbles

This report studies the generation, growth and collapse of transient single cavitation bubbles and also their luminescence. In conjunction with the experimental results, the dynamic process of the cavitation bubbles under a tension pulse is simulated by the use of the Rayleigh-Plesset equation.We choose, for the comparison of the differences in these effects, five different liquids: acetone, alcohol, water, glycerin and silicon oil.In our experiments, the dynamics of the cavitation bubbles and a high speed CCD and a piezoelectric transducer record the sound fields in the liquids respectively and simultaneously. It is found that the acoustic cavitation bubble begins to grow when a negative pressure pulse appears in the pressure signal of the sound field. After reaching usually very large maximum size (of the order of centimeter in radius), the bubble begins to shrink until it collapses when a strong shock is generated. After analyzing the sound fields signal, we conclude that during the sudden arrest of the glass tube, a tension wave is produced in the water column, starting from the tube bottom and traveling upwards, which makes the bubble nucleus grow, shrink and then collapse.The dynamic processes of the cavitation bubbles in five liquids are not the same. The behaviors of the cavitation bubbles in acetone and alcohol are very similar while that of the bubbles in water is slightly different. The behaviors of the cavitation bubbles in silicon oil and glycerin differ even more, but are similar between themselves.Our studies on the luminescence during bubbles'collapse show that the order of the luminescence intensity from weak to strong is as follows: acetone, alcohol, water, glycerin and silicon oil, which order is in agreement with the order of the vapor pressure of the liquids from strong to weak. It is also found that: 1) The luminescence intensity is related to the height of the liquid column; 2) The luminescence intensity of the transient single cavitation bubbles is about an order of magnitude higher than that of the continuous single bubble sonoluminescence; 3) The luminescence intensity of our cavitation bubbles in glycerin-water mixtures goes up as the glycerin concentration increases. Additionally, we find that there is weak luminescence when the bubble just begins to grow; this, as far as we are aware, is a phenomenon, not...