Xue Weizhao, Gao Wanjia, Liu Wenyi, Zhang Huixin, Guo Ruiqing
Key Laboratory of Instrumentation Science & Dynamic Measurement, Ministry of Education, North University of China, Taiyuan 030051, China.
Guangzhou Institute of Technology, Xidian University, Guangzhou 510555, China.
Sensors (Basel). 2022 Jul 4;22(13):5046. doi: 10.3390/s22135046.
The ultrasonic Lamb wave detection principle can realize the noncontact measurement of liquid level in closed containers. When designing an ultrasonic Lamb wave sensor, it is vital to thoroughly study and select the optimal wedge size at the front of the sensor. In this paper, firstly, we select the best working mode of Lamb waves according to their propagation dispersion curve in aluminum alloy, and we obtain the best angle of wedge through experiments. Secondly, we study the impact of the size of the wedge block on the results, and we obtain the selection method of wedge block parameters. The evaluations show that, when the frequency-thickness product is 3 MHz·mm, the Lamb waves work in the A1 mode, and the experimental effect is the best. At this time, the incident angle of the ultrasonic wave is 27.39°. The wedge thickness should be designed to avoid the near-field area of the ultrasonic field, and we should choose the length as odd multiples of 1/4 wavelength. The rules obtained from the experiment can effectively select the best working mode for ultrasonic Lamb waves, while also providing a basis for the design of the wedge block size in a Lamb wave sensor.
超声兰姆波检测原理可实现对密闭容器内液位的非接触测量。在设计超声兰姆波传感器时，深入研究并选择传感器前端的最佳楔块尺寸至关重要。本文首先根据兰姆波在铝合金中的传播色散曲线选择最佳工作模式，并通过实验获得最佳楔角。其次，研究楔块尺寸对结果的影响，得出楔块参数的选择方法。评估结果表明，当频率 - 厚度乘积为3 MHz·mm时，兰姆波以A1模式工作，实验效果最佳。此时，超声波的入射角为27.39°。楔块厚度的设计应避开超声场的近场区，且长度应选择为1/4波长的奇数倍。从实验中得出的规则能够有效选择超声兰姆波的最佳工作模式，同时也为兰姆波传感器中楔块尺寸的设计提供依据。
