Ultrasonic waveguide based level measurement using flexural mode F(1,1) in addition to the fundamental modes.
TL;DR: By monitoring all three wave modes simultaneously, a more versatile and redundancy in measurements of the fluid level inside critical enclosures of processing industries can be achieved by compensating for changes in the fluid temperature using one mode, while the level is measured using another.
Abstract: This paper reports on an ultrasonic waveguide sensor for liquid level measurements using three guided wave modes simultaneously. The fundamental wave modes longitudinal L(0,1), torsional T(0,1), and flexural F(1,1) were simultaneously transmitted/received in a thin stainless steel wire-like waveguide using a standard shear wave transducer when oriented at an angle of 45° to the axis of the waveguide. Experiments were conducted in non-viscous fluid (water) and viscous fluid (castor oil). It was observed that the flexural F(1,1) wave mode showed a change in both time of flight (due to the change in velocity and dispersion effects) and amplitude (due to leakage) for different levels (0-9 cm) of immersion of the waveguide in a fluid medium. For the same level of immersion in the fluid, the L(0,1) and the T(0,1) modes show only a relatively smaller change in amplitude and no change in time of flight. The experimental results were validated using finite element model studies. The measured change in time of flight and/or the shift in central frequency of F(1,1) was related to the liquid level measurements. Multiple trials show repeatability with a maximum error of 2.5% in level measurement. Also, by monitoring all three wave modes simultaneously, a more versatile and redundancy in measurements of the fluid level inside critical enclosures of processing industries can be achieved by compensating for changes in the fluid temperature using one mode, while the level is measured using another. This ultrasonic waveguide technique will be helpful for remote measurements in physically inaccessible areas in hostile environments.
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TL;DR: In this paper, the authors report the simultaneous generation of multiple fundamental ultrasonic guided wave modes (L(0, 1, T, 0, 1), and F(1, 1) on a thin wire-like waveguide and its interactions with liquid loading in different attenuation dispersion regimes.
Abstract: This paper reports the simultaneous generation of multiple fundamental ultrasonic guided wave modes L(0,1), T(0,1), and F(1,1) on a thin wire-like waveguide (SS-308L) and its interactions with liquid loading in different attenuation dispersion regimes. An application towards liquid level measurements using these dispersion effects was also demonstrated. The finite element method (FEM) was used to understand the mode behavior and their dispersion effects at different operating frequencies and subsequently validated with experiments. In addition, the ideal configuration for the simultaneous generation of at least two modes (L(0,1), T(0,1), or F(1,1)) is reported. These modes were transmitted/received simultaneously on the waveguide by an ultrasonic shear wave transducer aligned at 0°/45°/90° to the waveguide axis. Level measurement experiments were performed in deionized water and the flexural mode F(1,1) was observed to have distinct dispersion effects at various frequency ranges (i.e., >250 kHz, >500 kHz, and >1000 kHz). The shift in time of flight (TOF) and the central frequency of F(1,1) was continuously measured/monitored and their attenuation dispersion effects were correlated to the liquid level measurements at these three operating regimes. The behavior of ultrasonic guided wave mode F(1,1) when embedded with fluid at three distinct frequency ranges (i.e., >250 kHz, >500 kHz, and >1000 kHz) were studied and the use of low frequency Regime-I (250 kHz) for high range of liquid level measurements and the Regime-II (500 kHz) for low range of liquid level measurements using the F(1,1) mode with high sensitivity is reported.
7 citations
TL;DR: In this paper, the authors focused on the interconversion process of axisymmetric modes for incident longitudinal modes when interacting with the defects in pipeline whist ignoring the converted non-axisymmetric modes through suppressing them in reception.
Abstract: The converted modes generated by mode conversion in guided waves-based inspection can provide plenty of defect information, and the reasonable usage of multiple wave modes can improve the results of defect inspection and evaluation. Axisymmetric longitudinal L(0,2) mode guided-waves is widely used in pipeline inspection currently, and the lower order longitudinal L(0,1) mode is easily excited simultaneously. This paper focuses the interconversion process of axisymmetric modes for incident longitudinal modes when interacting with the defects in pipeline whist ignoring the converted non-axisymmetric modes through suppressing them in reception. This process is defined as symmetric mode conversion in this research. The pattern of axisymmetric mode sequence during symmetric mode conversion is identified and the method is proposed to extract the converted axisymmetric mode components for analysis. The relationships between the defect features and the modes generated in symmetric mode conversion under the excitation of longitudinal mode waves are investigated. The conclusion obtained by numerical simulation is also experimentally verified using guided wave data from practical pipeline. The results show that longitudinal modes in symmetric mode conversion present the useful time and frequency characteristics, which provides the potential for establishing an effective defect inspection and evaluation method with longitudinal guided waves.
5 citations
TL;DR: In this article, an ultrasonic waveguide sensor for measuring fluctuations in a liquid level using leaky longitudinal wave L(0,2) in a coolant loop system was presented.
Abstract: This Letter presents an ultrasonic waveguide sensor for measuring fluctuations in a liquid level using leaky longitudinal wave L(0,2) in a coolant loop system. A 20% cold-worked D9 fuel pin clad tube of 1000 mm long, 6.6 mm outer diameter and 0.45 mm wall thickness was used as a waveguide on which the L(0,2) mode was transmitted/received along the axial direction at 500 kHz. When the waveguide got introduced into a coolant loop and partially immersed in a non-viscous liquid (water/liquid sodium), the amplitude of L(0,2) mode got reduced due to leakage. The rate of leakage depends on the characteristics of the waveguide and the embedding liquid medium. By utilising this physical property of L(0,2) mode, it is possible to predict the variations in liquid level during dynamic conditions. Experimental measurements were carried out on a mock-up test loop in which water was used as embedding liquid and two artificial notches were made on the waveguide at different depths were used as reference levels. The time-amplitude signals were monitored and the reflected energies from the bottom end of the waveguide and the notches were used as the threshold and reference amplitudes respectively for identification of water level.
4 citations
25 Oct 2020
TL;DR: In this paper, a novel ultrasonic guided wave-based waveguide sensor for liquid level measurement is presented, which is suitable for enhanced level measurement using two wavemodes simultaneously.
Abstract: This paper reports a novel ultrasonic guided wave-based waveguide sensor for liquid level measurement which is critical for process controls in industries. A thin stainless wire with a varying cross-section (cylinder and rectangular end) is selected as the waveguide sensor in which all three fundamental wavemode L (0,1), T (0,1), and F (1,1) are excited and received by a single shear transducer. We validated the suitability of this waveguide for continuous level measurement experiments in the laboratory conditions. Level measurement experiments were carried out in inviscid fluid (water) and the fluid level is monitored/extracted by tracking the change in time of flight ((δTOF) of the excited torsional wavemode T(0,1) and flexural wavemode F(1,1) in the waveguide that is directly related to the fluid level in the probed media. The presented technique is suitable for enhanced level measurement using two wavemodes simultaneously. The versatility of this technique enables its application for remote measurements in a wide range of applications Keywords: Guided wave, Waveguide, Sensor, Level Measurement
3 citations
TL;DR: In this article, a simple, passive, single-element ultrasonic transducer is proposed for non-invasive measurements, operating at different resonant modes allows the adaptation of the emitted sound pattern to various requirements.
Abstract: A simple, passive, single-element ultrasonic transducer is proposed for non-invasive measurements. Operating the transducer at different resonant modes allows the adaptation of the emitted sound pattern to various requirements. The emitted sound field is simulated and experimentally characterized. We demonstrate the suitability of the transducer prototype for non-invasive continuous level measurement in laboratory as well as field environment over an extended level- and temperature range. The measured performance fulfils typical requirements for invasive level sensors. The versatility of the transducer enables its application in a wide range of non-invasive measurements.
2 citations
Cites background from "Ultrasonic waveguide based level me..."
..., guided-wave radar [26], guided-wave ultrasonic [27] or fiber-optic [28] technologies) require direct contact with the medium, but even non-contact technologies (applying, e....
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References
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TL;DR: A semianalytical finite element method is developed to model accurately the propagation velocity and leakage of guided waves along an immersed waveguide with arbitrary noncircular cross section and Experimental results obtained with a rectangular bar in a range of fluids show very good agreement with the theoretical predictions.
Abstract: Guided torsional waves in a bar with a noncircular cross section have been exploited by previous researchers to measure the density of fluids. However, due to the complexity of the wave behavior in the noncircular cross-sectional shape, the previous theory can only provide an approximate prediction; thus the accuracy of the measurement has been compromised. In this paper, a semianalytical finite element method is developed to model accurately the propagation velocity and leakage of guided waves along an immersed waveguide with arbitrary noncircular cross section. An accurate inverse model is then provided to measure the density of the fluid by measuring the change of the torsional wave speed. Experimental results obtained with a rectangular bar in a range of fluids show very good agreement with the theoretical predictions. Finally, the potentials to use the model for sensor optimization are discussed.
67 citations
TL;DR: The possibility of using ultrasonic guided waves for monitoring the cure process of epoxy resins is investigated and the numerical methods to relate these to the material properties of the curing resin are presented.
Abstract: The possibility of using ultrasonic guided waves for monitoring the cure process of epoxy resins is investigated. The two techniques presented use a wire waveguide which is partly embedded in the resin. The first technique is based on the measurement of attenuation due to leakage of bulk waves into the resin surrounding the waveguide. The second technique measures the reflection of the guided wave that occurs at the point where the waveguide enters the resin. Both the attenuation and the reflection coefficient change significantly during cure, and the numerical methods to relate these to the material properties of the curing resin are presented in this paper. The results from the modeling are experimentally verified and show good agreement. The applicability of each testing method is discussed, and typical cure-monitoring curves are presented.
41 citations
TL;DR: In this article, a novel optical technique for the continuous measurement of the level and the volume of transparent liquids in a cylindrical container is reported, based on the principle of liquid level induced modulation in the solid angle of a divergent light beam incident on liquid surface.
Abstract: We report here a novel optical technique for the continuous measurement of the level and the volume of transparent liquids in a cylindrical container. This measurement technique is based on the principle of liquid level induced modulation in the solid angle of a divergent light beam incident on liquid surface. This technique has advantages of being a very sensitive and non-intrusive way of measurement. The proposed technique has been experimentally tested with clean water, colored water, diluted glycerin, and pure glycerin by using liquid containers having 100-, 250-, and 500-mL capacity. Measurement results provide the highest sensitivity in the case of a container having smallest diameter. The proposed system is capable of measuring the liquid level and volume with approximate resolutions down to 3.2 μm and 6.2 μL, respectively, in the case of a 100-mL container. The sensitivity is found to decrease with the increasing diameter of the container as well as with the decreasing optical transparency of the liquids, but increase with the increasing refractive indices of transparent liquids. And this technique has an appreciably larger dynamic range of measurement, good linearity, and repeatability in the measurement responses.
40 citations
TL;DR: In this article, an experimental procedure using ultrasonic waves propagating in a rod to simultaneously measure the viscosity and temperature of melts at high temperatures using a very small amount of sample and without any mechanical rotating equipment.
37 citations
TL;DR: A solid corrosion-resistant torsional waveguide of diamond cross section has been developed to sense, online and in real-time, the characteristics of the liquid in which it is submerged to sense the liquid content of a bubbly medium, the density of adjacent pure liquids, the equivalent density of liquid-vapor mixtures or particulate suspensions, a suspension's concentration, and the liquid level.
Abstract: A solid corrosion-resistant torsional waveguide of diamond cross section has been developed to sense, online and in real-time, the characteristics of the liquid in which it is submerged. The sensor can measure, among other things, the liquid content of a bubbly medium, the density of adjacent pure liquids, the equivalent density of liquid-vapor mixtures or particulate suspensions, a suspension's concentration, and the liquid level. The sensor exploits the phenomenon that the speed of propagation of a torsional stress wave in a submerged waveguide with a noncircular cross section is inversely proportional to the equivalent density of the liquid in which the waveguide is submerged. The sensor may be used to conduct measurements along distances ranging from 20 mm to 20 m and over a wide range of temperatures and pressures, e.g., from the cryogenic temperature of liquid nitrogen, -196 degrees C, up to hot pressurized water at 300 degrees C and 7 MPa. A self-calibrating three-zone sensor and associated electronics have also been developed to compensate for any sensor inaccuracies due to operation over a wide range of temperature. >
32 citations