利用激光测距仪测得铸造用超声辐射杆端面全局振幅及频率，基于 FFT 细化分析对所测振幅分析后得到辐射杆端面振幅整体分布特性，在铝熔体中，将钛板竖直置于超声辐射杆正下方，启动超声振动系统运行20 h，通过分析钛板空蚀区域探究超声在铝熔体中的空化区域，得出辐射杆的空化区域分布，空化区域为一椭球形且分界面明显，空化域最远可达变幅杆正下方68 mm，结合铝熔体中超声的空化阈值，推算出20 kHz 铸造用功率超声在铝熔体中传播的衰减系数。%The global ultrasonic amplitude and frequency of an ultrasonic radiation rod's end face was measured using a laser rangefinder,and the data obtained were analyzed by utilizing FFT zoom analysis technique to obtain the global amplitude distribution of the rod's end face.A titanium plate was placed under the ultrasonic radiation rod in molten aluminum.An ultrasonic vibration system was activated for 20 h to find the ultrasonic cavitation area in molten aluminum by analyzing the cavitation corrosion area of the titanium plate,then the caviation area distribution of the ultrasonic radiation rod was obtained.It was shown that the cavitation area of the rod is an ellipsoid with obvious boundaries,and the longest distance between the boundaries and the ultrasonic radiation rod is 68 mm.Moreover,the sound pressure attenuation coefficient of 20 kHz ultrasound was calculated with the ultrasonic cavitation threshold in molten aluminum.
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