Kumar Abhishek, Periyannan Suresh
Department of Mechanical Engineering, National Institute of Technology, Warangal 506004, Telangana, India.
Rev Sci Instrum. 2023 Jun 1;94(6). doi: 10.1063/5.0145684.
This paper reports an ultrasonic waveguide technique using U-shaped configurations to measure the fluid level. The longitudinal L(0,1) wave mode was propagated in the waveguide using through-transmission (TT) and pulse-echo (PE) techniques simultaneously using a single shear transducer. Initially, we used the Finite Element Method (FEM) to study the waveguide's wave propagation behavior while immersed in various fluids. Develop the level sensor using the waveguide's first and second pass signals, corresponding to TT and PE. We have performed the level measurement experiments based on the drop in amplitude and change in time of flight of the received sensor signals. Studied the sensor's sensitivity using TT1, PE1, TT2, and PE2 signals (1 and 2 represent first and second pass signals, respectively) with different fluid levels (petrol, water, castor oil, and glycerin). A comparison study was performed between straight waveguides using PE and U-shaped waveguides using TT techniques to find the limitations of waveguide sensors. During level-sensing experiments, the average error for U-shaped and straight waveguides was identified as 3.5% and 5.6%, respectively. We studied signal attenuation from straight and U-shaped waveguide sensors based on the sensor surface and dead-end region. In the designed U-shape waveguide, only the wave leakage effect was considered, avoiding the dead-end reflection during the immersion of the sensor in liquid and allowing for more fluid depth measurements. In addition, the U-shaped waveguide was further used for fluid-level sensing using three wave modes [L(0,1), T(0,1), and F(1,1)] simultaneously. This sensor can monitor fluid levels in hostile environments and inaccessible regions of power plants, oil, and petrochemical industries.
本文报道了一种采用U形结构的超声波导波技术来测量液位。纵向L(0,1)波模式在波导中传播，使用单个剪切换能器同时采用穿透传输（TT）和脉冲回波（PE）技术。最初，我们使用有限元方法（FEM）研究波导在浸入各种流体时的波传播行为。利用波导的第一和第二遍信号（分别对应TT和PE）开发液位传感器。我们基于接收传感器信号的幅度下降和飞行时间变化进行了液位测量实验。使用TT1、PE1、TT2和PE2信号（1和2分别代表第一和第二遍信号），在不同液位（汽油、水、蓖麻油和甘油）下研究了传感器的灵敏度。对采用PE技术的直波导和采用TT技术的U形波导进行了对比研究，以找出波导传感器的局限性。在液位传感实验中，U形和直波导的平均误差分别确定为3.5%和5.6%。我们基于传感器表面和死端区域研究了直波导和U形波导传感器的信号衰减。在设计的U形波导中，仅考虑了波泄漏效应，避免了传感器浸入液体时的死端反射，并允许进行更大液位深度的测量。此外，U形波导还进一步用于同时使用三种波模式[L(0,1)、T(0,1)和F(1,1)]进行液位传感。该传感器可监测发电厂、石油和石化行业恶劣环境及难以到达区域的液位。
