【摘要】 采用COMSOL和JMatPro软件对高温下换能器换能效率、声波衰减及波速进行了研究。结果表明:换能器的换能效率随管道温度升高而降低,在管道温度700℃下工作20 min后,相较于常温,线圈换能效率降低13. 90%;随着温度的升高,声波衰减与温度近似成指数关系,温度越高声波衰减越快,当管道温度为675℃时,相对于常温下,横波质点位移幅值减小约22%;波速随温度升高而降低,当被测件温度达到675℃时,相对于常温,横波的速度降低了约16%。对高温引起的声波幅值、相位变化问题给出了相应补偿算法,使得信号波包相位更加准确,回波更加明显,降低了误判的几率。更多还原

【Abstract】 In order to study the influence of high temperature on electromagnetic ultrasonic detection,COMSOL and JMatPro software are used to study the transducer energy conversion efficiency,acoustic attenuation and wave velocity at high temperature. The results show that the energy exchange efficiency of transducer decreases with the increase of pipeline temperature. After working at 700 ℃ for 20 min,the coil energy exchange efficiency decreases by 13. 90 %; with the increase of temperature,the acoustic attenuation is approximately exponential with temperature,and the higher the temperature,the faster the acoustic attenuation. When the pipeline temperature is675 ℃,the S-wave particle displacement amplitude decreases by 22 % compared with the normal temperature;When the temperature reaches 675 ℃,the S-wave velocity decreases by about 16 % compared with the normal temperature. Corresponding compensation algorithm for the change of amplitude and phase caused by high temperature is given,which makes the phase of signal wave packet more accurate,echo more obvious,and reduces the probability of misjudgment.更多还原