超声探头外声场在测量管道上的仿真分析

摘要

Aiming at problem that the signals acquired by ultrasonic probe which is placed in different position, the acoustic field distribution outside the probe in the pipe is established using finite element software COMSOL, and acoustic field distribution in the pipeline under the conditions of different frequencies and different acoustic attenuation coefficient is studied. The results show that while the acoustic frequency increases,the pointing angle decreases,the scope of the main beam of the pipe wall will decrease;while acoustic attenuation coefficient increases,the pointing angle is the same,but the sound pressure values within the scope of the main beam decrease. The conclusions show that the design of receiving probe position should be mainly determined by acoustic frequency. When the frequency is different,the zero point of sound pressure is different,the design position of the probe should stay away from the zero points,In addition,because of the intensity of the acoustic signal at the main axle is large,position of probe should be close to the main axle in order to obtain better measurement precision.%针对超声探头安置于测量管道不同位置时,获取信号不同这一问题,利用有限元软件COMSOL建立了探头外输送管道内的声场分布,研究了在不同声波频率和不同声衰减系数下,管道上的声场分布情况.研究表明:声波频率增大时,指向角减小,管道壁上的主声束范围也随之减小;声衰减系数增大时,指向角不变,但管道壁上主声束范围内的声压值减小.说明接收探头的设计位置应该主要根据声波频率确定.当频率不同时,声压为零的点不同,探头的设计位置应该避开声压为零的点,另外由于主轴处声信号的强度大,为了获得比较好的测量精度,探头位置应该尽量靠近主轴.