【摘要】 在1.65MHz、3W/cm2的超声空化场中,沿垂直声波辐射方向插入高分子材料ABS等试验板,板面上即刻出现熔化现象:超声空化场的一种热释放。若使这种空化场形成超声喷泉,其热释放的效果更加明显。采用圆柱形套管和圆锥形套管对这种超声喷泉进行聚束喷射,还可加剧这种热释放。作者认为,大量空化泡塌陷、爆裂时的高温声冲流和高压冲击波是使这种低导热系数试验板热变熔化的主要机制。超声喷泉中隐含的空化集中作用,以及聚束状态下附加的空化集中作用和声能密度的增加,则进一步增强了这种热释放。更多还原

【Abstract】 When a piece of thin test sheet made of large molecular material,for example ABS,was vertically immersed in cavitating water,a horizontal ultrasonic cavitation field with operating frequency of 1.65MHz and acoustic intensity of 3W/cm-2,a melting phenomenon appeared on the face of the sheet.The melting phenomenon was named for the heat release of ultrasonic cavitation field in this paper.Also the heat release could become apparently shouting shoutly if the cavitation field was set to jet upward and seem to be a fountain,and further could be increased when a cylindrical or cylindroconical plastic or glass tube was used to gather the ultrasonic fountain.The arthors think that both the heat flow with high temperature and the action of high-pressure shock wave generated by a great number of cavitating bubbles are responsible for the heat release of the ultrasonic field,and that the cavitation concentrating effect in the jetting ultrasonic fountain and the increments of acoustic energy density and concentrating cavitation bubbles in the gathering state of the ultrasonic fountain could intensify the heat release effect.更多还原