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.