Sound Velocity In Liquids Research Articles

Tubular phononic crystal sensor

We propose the design of a tubular phononic crystal (TPC) for the purpose of sensing the physical properties of a liquid filling the hollow part of the tube. The TPC is constituted by a periodic repetition of washers along a hollow pipe with the advantage of avoiding any perturbation of a flowing fluid by any element inside the tube. Using finite element simulations, we demonstrate the existence of complete as well as polarization dependent bandgaps inside which one can design localized modes associated with defects. The most sensitive cavity to the liquid sound velocity is found to be constituted by a Fabry–Pérot (F–P) cavity. The signature of the cavity modes can be detected as peaks or dips in the transmission spectrum as well as at the external surface of the cavity. We study the dramatic effect of the liquid viscosity, more particularly shear viscosity, on these features and discuss the conditions for their practical observation. A TPC test sample made of a polymer is fabricated by means of 3D printing and characterized without the liquid by transmission measurements. The comparison with the simulations showed the necessity of considering the damping of the polymer whose effect on the transmission features is discussed. Our sensor design can find many applications at different scales in several systems transporting a fluid as microfluidic channels in micro- and nanotechnologies, syringes in medicine, or pipelines in civil engineering.

Multi-strategy Measurement of High-resolution Ultrasonic TOF

Jiao, Y.; Li, Z.; Zhu, J., and Zhang, B., 2020. Multi-strategy measurement of high-resolution ultrasonic TOF. In: Zheng, C.W.; Wang, Q.; Zhan, C., and Yang, S.B. (eds.), Air-Sea Interaction and Coastal Environments of the Maritime and Polar Silk Roads. Journal of Coastal Research, Special Issue No. 99, pp. 389–395. Coconut Creek (Florida), ISSN 0749-0208.Ultrasonic transducers are widely used in liquid sound velocity measurement. Acquisition of time-of-flight (TOF) is the key technology of high precision measurement of sound velocity.In this paper, to measure TOF with high precision, a Multi-strategy Measurement technique is proposed, which is able to locate the region of interest of the signals received echo waveform, and the wavelet denoising is carried out. To evaluate the proposed method, in an identified environment, the experiments were performed under defined the distance between transmitter and receiver in pure water at 30°C. The experiments were performed that, in the sound velocity measurement, the method has a high adaptability, which can achieve the goal of removing noise and improving detection accuracy. Although this paper focus on sound velocity in pure water, the method described may also find application in air.

Sound velocity and equation of state in liquid cesium at high pressure and high temperature

Liquid cesium (l-Cs) sound velocity at high densities was investigated along a 500-K isotherm using high-pressure picosecond acoustics measurements. At 2.0 GPa, the liquid sound velocity goes through a maximum versus pressure without any change on the reflectivity and interferometry acoustic signals. Upon further compression, a softening of the l-Cs viscoelastic properties is observed from 2.0 up to 4.0 GPa, pressure at which the reflectometric signal is abruptly reversed whereas the interferometric signal remains qualitatively the same. This anomalous behavior could be related to an electronic transformation within the l-Cs state, which here again could reflect what happens at lower temperature within the solid state. If so, such liquid-liquid transition may be driven by the progressive collapse of the $6s$ electronic orbital onto the $5d$ ones. Above 4.0 GPa, the l-Cs sound velocity starts again to increase as commonly expected upon compression.

Liquid Sound Velocity and Density Decoupling on a Compact Lamb Wave Sensor by a Two-Port Local Resonating Method

A two-port local resonating (TPLR) method for thin-film Lamb wave sensor is proposed. Based on properties of multi-modes analyzed by numerical simulation and experimental measurement, the TPLR method is able to generate the second-order flexural mode A 02 (A 0i , i = 2). Density and sound velocity of liquid solutions can be decoupled based on the first-order flexural mode A 01 (A 0i , i = 1) and the A 02 mode, and solutions with the same density, such as CH 3 CH 2 OH and CH 3 OH, can be successfully distinguished on a single Lamb wave device. When the phase velocity of A 02 mode is close to the sound velocity of liquid, compared with the traditional delay-line configuration, smaller period of interdigital transducers and device miniaturization by the TPLR method can be realized. Generation of new modes with the TPLR method demonstrates an alternative for multi-parameters sensing of Lamb wave sensors.

Roe‐type Riemann solver for gas–liquid flows using drift‐flux model with an approximate form of the Jacobian matrix

SummaryThis work presents an approximate Riemann solver to the transient isothermal drift‐flux model. The set of equations constitutes a non‐linear hyperbolic system of conservation laws in one space dimension. The elements of the Jacobian matrix A are expressed through exact analytical expressions. It is also proposed a simplified form of A considering the square of the gas to liquid sound velocity ratio much lower than one. This approximation aims to express the eigenvalues through simpler algebraic expressions. A numerical method based on the Gudunov's fluxes is proposed employing an upwind and a high order scheme. The Roe linearization is applied to the simplified form of A. The proposed solver is validated against three benchmark solutions and two experimental pipe flow data. Copyright © 2015 John Wiley & Sons, Ltd.

Resonant pressure wave setup for simultaneous sensing of longitudinal viscosity and sound velocity of liquids

Increasing demands for online monitoring of liquids have not only resuted in many new devices relying on well-established sensing parameters like shear viscosity but also initiated research on alternative parameters. Recently, the longitudinal viscosity has been evaluated as a promising candidate because the devices arising enable the bulk of the liquid to be probed rather than a thin surface layer. We report on a multi-purpose sensor which allows simultaneous measurement of the sound velocity and longitudinal viscosity of liquids. The device embodiment features a cube-shaped chamber containing the sample liquid, where one boundary surface carries a flush-mounted PZT transducer. In operation, the transducer induces standing, resonant pressure waves in the liquid under test. We studied the influences of sound velocity and longitudinal viscosity on the generated pressure waves by means of the Navier–Stokes equation for adiabatic compressible liquids and exploited both parameters as the basic sensing mechanism. Furthermore, a three-port network model describing the interaction of the transducer and sample liquid was developed in order to be applied for extracting the parameters of interest from the raw measurement data. Finally, we demonstrate the device and method by carrying out and discussing test measurements on glycerol–water solutions.

Liquid sensor utilizing a regular phononic crystal with normal incidence of sound

A phononic crystal device is investigated as sensor platform utilizing resonant transmission. Here, we use a phononic crystal plate consisting of a solid matrix and liquidfilled holes. The device is fully immersed into the liquid in such a way that the incidence direction of sound is normal to the plate. A characteristic transmission peak, calculated using finite-difference time-domain (FDTD) and determined with two different experimental setups, has been found to strongly depend on the liquid sound velocity. The peak maximum frequency serves as measure for liquid composition.

Experimental method of measuring sound velocity using ultrasonic flowmeter

In order to obtain sound velocity in liquid, an experimental method of measuring sound velocity is designed. A time-difference type ultrasonic flowmeter and normal flow checkout equipment are used to measure the flow speed of liquid in closed hydraulic pipeline simultaneously, then the measured value and the true value of the flow rate are measured, and the meter-factor of the ultrasonic flowmeter is determined. Furthermore, the relationship between the sound velocity and the meter-factor is derived under a certain condition. Based on the method, the velocity of sound in dinitrogen tetroxide (N2O4) at 7.6-19.4 ℃ and unsymmetric dimethyl hydrazine ((CH3)2NNH2) at 6.5-25.2 ℃ are measured at 0.17 MPa. It provides reference for measuring the sound velocity in other liquid.

2D Phononic Crystal Sensor with Normal Incidence of Sound

This contribution shows the sensor application of a resonance-induced extraordinary transmission through a regular phononic crystal consisting of a metal plate with a periodic arrangement of holes in a square lattice at normal incidence of sound. The characteristic transmission peak has been found to strongly depend on liquid sound velocity. The respective peak maximum frequency can therefore serve as measure for liquid analysis. Experimental verification has been performed with mixtures of water and propanol as model system. Numerical calculations based on COMSOL and EFIT reveal more insides to the wave propagation characteristics. Experimental investigations with Schlieren method and laser interferometry support the theoretical findings.

Sound velocity in liquid and glassy selenium

The speed of longitudinal sound waves at 7 and 22MHz has been measured in liquid, supercooled, and amorphous selenium, including the region around the glass transition temperature, Tg, near 35°C. In amorphous selenium the speed of shear waves at 7MHz was also measured. The experiments were performed with high purity Se (99.9999%) hermetically sealed in an evacuated silica ampoule. Four temperature regions with strongly different relaxation times can be distinguished between room temperature and the melting point: (1) a glassy state below Tg, which is stable on the time scale of the experiments, (2) a glassy state above Tg, which is metastable on the time scale of the experiments, (3) a region where homogeneous crystal nucleation occurs, and (4) a supercooled liquid, which is stable on the time scale of the experiments. Each region is marked by a change in the slope of the temperature dependence of the sound velocity. Near the glass transition temperature the velocities of longitudinal and transverse sound exhibit hysteresis with a step-like drop on heating and a more continuous rise on cooling. The step-like anomaly in sound velocity may be a general property of the glass transition.

Response of an infinite free plate–liquid system to a moving load: Theoretical stationary response in the subsonic case

An unbounded system consisting of a plate in contact with a liquid is considered. The coupling equations are summarised, accounting for the compressibility of the liquid and the Mindlin–Reissner plate theory. An analytical solution is sought in the one-dimensional case, for a load that travels at a constant velocity, subsonic with respect to the liquid sound velocity. The work completes results already obtained for the supersonic case. The steady-state solution is theoretically established for a moving force and is explicit for displacements, transverse deflexion and cross-sectional rotation, for flexural and shearing stresses in the plate and for pressure and velocities in the liquid. All results are in a non-dimensional form and contain as few parameters as possible. Graphs and curves are added which provide results for any aluminium or steel plate coupled with water, whatever the subsonic velocity of loading. A numerical part completes the study and reveals that, when a moving force travels across a large coupled plate at a constant velocity, a part of the response evolves progressively towards the steady-state response. Comparison shows that the transient numerical solution to a stationary loading converges to the theoretical stationary response.

The Schoch effect to distinguish between different liquids in closed containers

In different industrial branches, it is necessary to characterize liquids in closed containers. For small cans, accessibility to both sides is almost trivial. However, in industries in which larger containers are used, and especially in the dock industry, only one side is accessible practically; and damping often prevents through-transmission ultrasonic measurements or pulse echo techniques. It is known that built-in sensors can be used to determine density and wave velocity of liquids; but normally containers are not equipped with such sensors. It is also known that differences in the reflection coefficient at a solid-liquid interface can determine the density and sound velocity of liquids, but only if the difference in acoustical impedance between the solid and the liquid is small. For most containers this condition is not provided; therefore, a more sensitive method is needed. This paper reports simulations that show how identical containers, having different liquids inside, can be distinguished from one another by means of differences in the Schoch effect at a Lamb wave angle of incidence for harmonic-bounded ultrasonic beams.

Frequency-to-Time Converter for Measuring Sound Velocity in Liquids

The measuring converter is based on the principle of tracking the balancing of the separated informative value of the interval probed by an acoustic pulse in the studied medium at a given basic distance by a pulse period divisible by the period of pulses of a frequency-controlled generator. A high accuracy is reached by excluding an inconclusive (spurious) time delay of the acoustic and electric signals in the acoustic converter and electronic operational units. The acoustic base-line distance of the measuring converter is 0.1 m, the measurement range is 1400–1600 m/s, the output signal has a frequency of 140–160 kHz, the absolute basic error is ≤ ±0.015 m/s, and the time to reach a steady-state output signal is ≤0.6 s.

High resolution and small volume automatic ultrasonic velocimeterfor liquids

A method is described to precisely measure the sound velocity ofliquids. The construction of a resonator cell for the simultaneous measurementof a sample liquid and a reference liquid is presented. The non-idealproperties of the cavity resonators are carefully considered for a superiorevaluation of the resonance frequency data. Also presented is a low-pricedelectronic set-up, designed for the computer-controlled determination of thecomplex transfer functions of the cavity resonators and also for automatictemperature monitoring and control. Possible sources of errors are discussedand some representative results are presented in order to illustrate therepeatability of the method and the accuracy of the sound velocity datarelative to a reference liquid.

Ultrasonic Measurement of Sound Velocity in Liquids by a Phase-Locked Loop

This paper describes a new ultrasonic technique for measuring the velocity of sound in liquids which relies on a phase-locked loop method to automatically eliminate dependence of the result on temperature. An empirical equation using NaCl solutions as test liquids within a concentraion range of 0.0–5.0% and a temperature range of 15–45°C was obtained by analyzing the various sound velocities by the least squares method. An empirical equation was derived to design a compensatory voltage-controlled oscillator (Comp VCO) which would automatically eliminate the strong temperature dependence of the measured sound velocity in liquids. The sound velocity after eliminating temperature dependence was easily obtained from the output frequency of the Comp VCO by multiplying the coefficient. A system with a Comp VCO circuit was applied to NaCl solutions of varying concentrations and was shown to yield velocities accurate to within 0.024% independent of temperature variations of ±1.3°C at approximately 24.9°C.

Dynamic properties of simple liquids: Dependence on the softness of the potential core

The dependence of both individual and collective dynamic properties of simple liquids on the steepness of the potential cores is analyzed. Molecular dynamics simulations of liquids in identical conditions but assuming two repulsive interaction potentials with very different softness have been carried out. Two liquids at very different densities (with volume packing fractions η=0.5 and η=0.3) have been considered for each potential. The study of the dynamic collective properties includes the dynamic structure factor and the longitudinal and transverse current correlations. It has been corroborated that longitudinal modes associated with density fluctuations propagate up to higher wave numbers in liquids with softer potential cores. However, the propagating transversal modes in dense liquids are weakly influenced by the hardness of the potential core. Other properties such as the sound velocity in liquids at high density or the dynamic structure factor at the kinetic regime are rather insensitive to the details of the repulsive interactions. The velocity correlation functions for liquids with soft repulsive potential walls are markedly oscillatory. These oscillations are associated with the coupling of the atomic velocity to collective density fluctuations.

Measurement of the Sound Velocity in Liquids Using a Leaky Lamb Wave Transducer Composed of a Layer-Structured Substrate

A leaky Lamb wave transducer composed of a thin piezoelectric ceramic plate and a thin glass plate is described for the purpose of measuring the sound velocities in liquids. The propagation characteristics of leaky Lamb waves are numerically analyzed first and the operational characteristics of the transducer are experimentally demonstrated by measuring the frequency dependence of the admittance and the radiation angle of the longitudinal wave into the liquid. The sound velocities in the saline solution of different concentrations are estimated by sweeping the operation frequency. This transducer has an operation mode with a wide frequency range in which three propagation modes of leaky Lamb waves are involved, which is favorable for this application.

Automatic Ultrasonic Measurement of Sound Velocity in Liquids by a Phase Difference Method

The working of a novel ultrasonic technique for measuring the sound velocity in liquids, which automatically cancels the dependence of temperature by a phase difference method is described in this paper. This technique uses a very simple circuit system which treats only the continuous sinusoidal waves and is constituted of only analog circuits. The temperature-compensation factor in the designing of the temperature-compensation circuit is derived from the equation obtained for the ultrasonic velocity in sea water. This measuring system is shown to yield a 0.01% accuracy of velocity determination, independent of the temperature variation of ±1.0°C around 25.4°C for the NaCl solution.

Miniaturized ultrasonic sensor system for liquid analysis

At the moment, known commercial devices to measure the sound velocity in liquids are limited in their application because the relation between velocity and concentration of substances is often not clear, for instance, if it is a parabolic curve. Additionally, the temperature dependence shows similar behavior. This contribution will present an ultrasonic sensor system consisting of a miniaturized multisensor arrangement for the comprehensive acoustic characterization of liquid mixtures. The sensor is based on segmented cylindrical piezoceramics and measures velocity, impedance coefficient, attenuation coefficient, and temperature. If it is a known liquid mixture it is possible to use the measuring quantities to calculate the material properties acoustical impedance and absorption or the concentration of selected substances in complex liquids. The sensor system is able to adapt itself to different and changeable absorption conditions which is typical of industrial processes. The measuring chamber is optimized to investigate small volumes of liquid specimens. In this contribution the sensor design and the developed approach for the continuous and simultaneous measurement of acoustic properties of liquids will be described. Application examples of the sensor in the chemical and food industry will show the advantages and limits of our new sensor system.

Accurate measurements of the sound velocity in pure water by combining a coherent phase-detection technique and a variable path-length interferometer

An automated system for measuring the sound velocity in liquids has been developed by combining a coherent phase-detection technique and a variable path-length interferometer, in which a sample liquid is filled between an ultrasonic buffer and a moving reflector, and phase changes of a given echo of the ultrasonic pulse is measured by a phase-sensitive detector (PSD) as a function of changes in the acoustic path length. For the accurate determination of the changes in the acoustic path length, the displacement of the moving reflector is measured by a Michelson interferometer that is illuminated by a frequency-stabilized He–Ne laser. The sound velocity is determined from a direct comparison of the acoustic wavelength in the sample liquid with the optical wavelength of the laser. In order to check the performance of the apparatus, measurements were performed for distilled water in the temperature range 20–75 °C under atmospheric pressure with a carrier frequency of 16.5 MHz. The precision of the phase measurements by the PSD and systematic errors in the sound velocity measurement are evaluated. The total uncertainty of the sound velocity is estimated to be 0.001%. The results agree with reliable literature values within 0.003%.