Ultrasonic Sensor for the Presence of Oily Contaminants in Water (original) (raw)
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Sensor Ultrasonico Para La Presencia De Contaminantes Oleosos en Agua
2012
The determination of the complex reflection coefficient of ultrasonic shear-waves at the solid-liquid interface is a technique employed for the measurement of the viscoelastic properties of liquids. An interesting property of the measurement technique is the very small penetration depth of the shear-waves into the liquid sample, which permits measurements with liquid films of some micrometers thick. This property, along with the adhesion of oily substances to surfaces, can be used for the detection of oily contaminants in water. In this work, the employment of the ultrasonic shear-wave reflection technique to the detection of oily contaminants in water is proposed and the theoretical and experimental concepts involved are discussed. Preliminary experimental results show the measurement technique can detect SAE 40 automotive oil in water in volume proportions less than 0.5%.
A Method for the Measurement of Hydrodynamic Oil Films Using Ultrasonic Reflection
Tribology Letters, 2004
The measurement of the thickness of an oil film in a lubricated component is essential information for performance monitoring and control. In this work a new method for oil film thickness measurement, based on the reflection of ultrasound, is evaluated for use in fluid film journal bearing applications. An ultrasonic wave will be partially reflected when it strikes a thin layer between two solid media. The proportion of the wave reflected depends on the thickness of the layer and its acoustic properties. A simple quasi-static spring model shows how the reflection depends on the stiffness of the layer alone. This method has been first evaluated using flat plates separated by a film of oil, and then used in the measurement of oil films in a hydrodynamic journal bearing. A transducer is mounted on the outside of the journal and a pulse propagated through the shell. The pulse is reflected back at the oil film and received by the same transducer. The amplitude of the reflected wave is processed in the frequency domain. The spring model is then used to determine the oil film stiffness that can be readily converted to film thickness. Whilst the reflected amplitude of the wave is dependent on the frequency component, the measured film thickness is not; this indicates that the quasi-static assumption holds. Measurements of the lubricant film generated in a simple journal bearing have been taken over a range of loads and speeds. The results are compared with predictions from classical hydrodynamic lubrication theory. The technique has also been used to measure oil film thickness during transient loading events. The response time is rapid and film thickness variation due to step changes in load and oil feed pressure can be clearly observed.
Viscosity measurement in thin lubricant films using shear ultrasonic reflection
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2008
When a shear ultrasonic wave is incident on a solid and liquid boundary, the proportion that is reflected depends on the liquid viscosity. This is the basis for some instruments for on-line measurement of bulk liquid viscosity. In machine elements, the lubricant is usually present in a thin layer between two rubbing solid surfaces. The thin film has a different response to an ultrasonic shear wave than liquid in bulk. In this work, this response is investigated with the aim of measuring viscosity in situ in a lubricating film. The proportion of the wave reflected at a thin layer depends on the layer stiffness. A shear wave is reflected by the shear stiffness of the thin layer. For a thin viscous liquid layer, the stiffness is a complex quantity dependent on the viscosity, wave frequency, and film thickness. This stiffness is incorporated into a quasi-static spring model of ultrasonic reflection. In this way, the viscosity can be determined from shear-wave reflection if the oil-film ...
Proceedings of the 21st IEEE Instrumentation and Measurement Technology Conference (IEEE Cat. No.04CH37510), 2004
In the oil industry, many applications require the measurement of more than one liquid level interface, often in challenging environments. In this paper, an ultrasonic technique has been developed to examine the propagation of ultrasonic waves in the oil, water, and mixed oil-water liquids. The technique is expanded to determine the oil, emulsion, and water levels in an oil tank. A dedicated compact, low-cost, and programmable ultrasound-based Multi-layer level measurement (MLLM) device has been designed and implemented. The advantages of the new method over the current methods include contactless distance measurement, higher accuracy, lower cost, user friendly, simpler setup, and using non-nuclear rays. Additionally, the use of ultrasonic waves for the measurement has the advantage over light-based methods of being insensitive to dusty and smoky environment and almost independent of the object material and surface. Preliminary experiments have been conducted on the device. In this paper, the design and operating parameters of this device are discussed and evidence for the satisfactory performance is given.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2015
The apparent viscosity of oils in the thin layers that exist in machine elements such as gears and bearings is very different to that in the bulk. In addition, oils in lubricating layers are characterized by non-Newtonian behaviour due to the severe thermodynamic conditions that arise. It is this viscosity that determines the film thickness in lubricated mechanical components. This paper describes a novel methodology based on an ultrasonic approach to determine viscosity in situ in a lubricated contact. The methodology considers the lubricant at the solid boundary as a Maxwell viscoelastic fluid and determines its response to an ultrasonic wave. This approach is then compared with existing methodologies in both a static contact and in a rotating journal bearing. The obtained results have shown that the algorithm proposed in this study is most suitable to study lubricants in the range of 0.3–3 Pas and the measurement error has been found to be less than 10%. This viscosity range is c...
Ultrasonics, 2019
In-situ measurement of viscosity advances the field of rheology, and aides the development of sensing systems for condition and performance monitoring of lubricated mechanisms. Many lubricated mechanisms, such as journal bearings or seals, are characterised by three-layer interfaces; an oil separating two solid (usually metallic) bodies. The viscoelastic study of the lubricating oil in layered systems is possible in-situ by means of ultrasonic reflection (Schirru et al. (2015)). General solutions exist for the reflection of longitudinal plane waves from multi-layered solid-fluid systems. Similar solutions can be applied to plane shear waves. The use of a quarter-wavelength intermediate matching layer improves the sensitivity of the ultrasonic measurement and overcomes problems of acoustic mismatch. This opens the possibility of using reflectance methods to measure engineering (metal-oil) bearing applications that are acoustically mismatched. In this paper, a rigorous mathematical model for wave propagation in a three-layer system is solved for the reflection coefficient modulus and validated using a quarter wavelength ultrasonic viscometer. The model was tested against experimental data for two Newtonian reference fluids, water and hexadecane, and for one non-Newtonian reference fluid, squalene plus polyisoprene (SQL + PIP), measured ultrasonically at frequencies between 5 and 15 MHz. The results are in agreement with the expected viscosity values for the reference fluids. Further, the viscosity measurement is not limited to the resonance frequency, but it is performed over a broad band frequency range. This is important to improve measurement confidence and accurate spectroscopy measurement for the determination of viscoelastic properties.
Applications of Acoustic Wave Devices for Sensing in Liquid Environments
Applied Spectroscopy Reviews, 2006
Acoustic wave devices such as thickness shear mode (TSM) resonators and shear horizontal surface acoustic wave (SH-SAW) devices can be utilized for characterizing physical properties of liquids and for chemical sensor applications. Basic device configurations are reviewed and the relationships between experimental observables (frequency shifts and attenuation) and physical properties of liquids are presented. Examples of physical property (density and viscosity) determination and also of chemical sensing are presented for a variety of liquid phase applications. Applications of TSMs and polymer-coated guided SH-SAWs for chemical sensing and uncoated SH-SAWs for "electronic tongue" applications are also discussed.
Chemical Engineering and Processing: Process Intensification, 2006
This paper presents an experimental study to investigate the suitability of thick-film ultrasonic transducers for composition measurements in heterogeneous mixtures. Following on from earlier developments [G. Meng, A.J. Jaworski, T. Dyakowski, J.M. Hale, N.M. White, Design and testing of a thick-film dual-modality sensor for composition measurements in heterogeneous mixtures, Meas. Sci. Technol. 16(4) (2005) 942-954], focused on the design and preliminary testing of the transducers for mixtures of vegetable oil and salty water, the current paper looks in more detail into their application to industrially relevant fluids, namely crude oil and process water, which are common in oil and gas extraction and petrochemical industries. The measurements are based on the time-of-flight of the ultrasonic pressure wave in order to obtain the speed of sound. The results, showing the variation of the speed of sound with the volume fraction of crude oil, for three different temperatures, are compared with five theoretical models available in the existing literature. It is shown that the models proposed by Urick [R.J. Urick, A sound velocity method for determining the compressibility of finely divided substances, J. Appl. Phys. 18 (1947) 983-987] and by Kuster and Toksöz [G.T. Kuster, M.N. Toksöz, Velocity and attenuation of seismic waves in two-phase media. Part I. Theoretical formulations, Geophysics 39 (1974) 587-606] provide a relatively accurate prediction for the speed of sound in the media studied. Interestingly, the model developed by Povey and co-workers [V.J. Pinfield, M.J.W. Povey, Thermal scattering must be accounted for in the determination of adiabatic compressibility, J. Phys. Chem. B 101 (1997) 1110-1112] only agrees with experiment when its thermal scattering features are neglected. Overall, the results obtained demonstrate that the slim-line and compact thick-film transducers can be considered as a viable means for the composition measurements in the process conditions.
Ultrasonic oil-film thickness measurement: An angular spectrum approach to assess performance limits
The Journal of the Acoustical Society of America, 2007
The performance of ultrasonic oil-film thickness measurement is explored. A ball bearing (type 6016, shaft diameter 80 mm, ball diameter 12.7 mm) is used with a 50 MHz focused ultrasonic transducer mounted on the static shell of the bearing and focused on the oil film. In order to explore the lowest reflection coefficient and hence the thinnest oil-film thickness that the system can measure, three kinds of lubricant oils (Shell T68, VG15 and VG5) with different viscosities were tested. The results