Experimental Speeds Of Sound Research Articles

Thermodynamic Properties of 1-Butanol + Ethyl Laurate Binary Mixtures by Combining Experimental Speeds of Sound with Volume Translated Peng–Robinson Equation of State

Thermodynamic Properties of 1-Butanol + Ethyl Laurate Binary Mixtures by Combining Experimental Speeds of Sound with Volume Translated Peng–Robinson Equation of State

Gaseous speed of sound and virial coefficients for 2,3,3,3-tetrafluoropropene (R1234yf) + 1,1,1,2-tetrafluoroethane (R134a) binary mixture

The binary mixture 2,3,3,3-tetrafluoropropene (R1234yf) + 1,1,1,2-tetrafluoroethane (R134a) is commercially interesting and is widely studied in thermodynamics properties, but except for gaseous speed of sound. In this work, we modified the experimental procedure of the cylindrical fixed-path acoustic resonance method for the sound speed measurement of mixtures. Then we obtained the first two sets of gaseous sound speed data at the molar fraction of about (0.207/0.793) and (0.580/0.420) with a combined relative expanded uncertainty (k = 2) of 0.03%. The accurate molar fractions along each isotherm line were determined by extrapolating the experimental data with the absolute expanded uncertainty (k = 2) of 0.003. The interaction virial coefficients were derived from the experimental sound speed data and were used to establish a hard-core square-well molecular potential model. A previous virial coefficient correlation was modified to predict the virial coefficients for mixtures. The experimental results and model calculations agree well with each other, confirming the correctness of the experimental method. The data could provide references to test and develop the mixing model.

Experimental Speed of Sound for 3,3,3-Trifluoropropene (R-1243zf) in Gaseous Phase Measured with Cylindrical Resonator

The speed of sound in 3,3,3-trifluoropropene (R-1243zf) in the gaseous phase has been measured using a fixed-path cylindrical resonator. The experiment was conducted along nine quasi-isochoric line...

Effect of nonideal fluid behavior on the jet mixing process under high-pressure and supersonic flow conditions

The mixing process of extremely underexpanded supercritical jets into a gaseous environment is studied. The focus lies on the influence of the nonideal fluid behavior on the mixing process. Numerical simulations are conducted for eight different injection conditions where experimental sound speed measurements are available. Overall, a very good agreement between simulations and experiments is found. A comparison of the real-gas and the ideal-gas closures shows the necessity to account for nonideal fluid behavior. The application of the ideal-gas law results in an incorrect energetic state which most prominently leads to an overestimation of the post-shock temperature by 70 K. The wrong energetic state yields erroneous thermodynamic properties in the mixing region. Finally, a mixture model is deduced enabling the prediction of mixture properties. As independent measurements of mass/mole fractions are not available, this evaluation procedure is a first attempt to numerically predict the mixture composition in underexpanded jets.

Molecular interaction studies based on transport, thermodynamic and excess properties of aniline and alkanol mixtures at varying temperatures

Density (ρ) data at 303.15 K–318.15 K, Sound speed (u) and viscosity (η) data at 303.15 K–313.15 K for the binary mixtures of aniline with 1-alkanols were measured over the entire composition range. The 1-alkanols included in this work were 1-propanol, 1-butanol, 1-pentanol and 1-hexanol. The experimental data were used to compute excess molar volume (VmE), excess isentropic compressibility (кSE) and deviation in viscosity (Δη). The excess data and deviation in viscosity (Δη) data were analyzed and correlated using Redlich-Kister and Hwang polynomial type equations. Also the experimental sound speed data were considered in terms of Schaff's collision factor theory (CFT) and Jacobson free length theory (FLT). Further, for all the measured viscosity values, the average absolute percentage deviation (AAPDs) values were obtained using various predictive and correlative models and the results were compared for prognostic analysis. Furthermore, the deviations of the measured properties in the investigation were examined in terms of divergent intermolecular interactions that exist among the constituent molecules.

A Reference Equation of State for Heavy Water

An empirical fundamental equation of state (EOS) is presented for fluid heavy water (deuterium oxide, D2O). The equation is explicit in the reduced Helmholtz energy and allows the calculation of all thermodynamic properties over the whole fluid surface. It is valid from the melting-pressure curve up to a temperature of 825 K at pressures up to 1200 MPa. Overall, the formulation represents the most accurate measured values and almost all other available data within their experimental uncertainty. In the homogeneous liquid and vapor phase, the expanded relative uncertainties of densities calculated from the EOS are mostly 0.1% or less; liquid-phase densities at atmospheric pressure can be calculated with an uncertainty of 0.01%. The speed of sound in the liquid phase is described with a maximum uncertainty of 0.1%; the most accurate experimental sound speeds are represented within their uncertainties ranging from 0.015% to 0.02%. In a large part of the liquid region, the isobaric heat capacity is represented with an uncertainty of 1%. The uncertainty in vapor pressure is mostly within 0.05%. In the critical region, the uncertainties of calculated properties are in most cases higher than the values above, but the EOS enables a reasonable description of this region. The equation matches available data for the metastable subcooled liquid, and it extrapolates in a qualitatively correct way to extreme values of temperature and pressure. This formulation is the result of an effort to establish a new standard for the thermodynamic properties of heavy water by the International Association for the Properties of Water and Steam.

Acoustical characterization of polysaccharide polymers tissue-mimicking materials

Tissue-mimicking phantoms play a crucial role in medical ultrasound research because they can simulate biological soft tissues. In last years, many types of polymeric tissues have been proposed and characterized from an acoustical and a thermal point of view, but, rarely, a deep discussion about the quality of the measurements, in terms of the uncertainty evaluation, has been reported. In this work, considering the necessity to develop laboratory standards for the measurement of ultrasonic exposure and dose quantities, a detailed description of the experimental apparatuses for the sound speed and the attenuation coefficient measurements is given, focusing the attention on the uncertainty evaluation both of the results and analysis algorithms. In particular, this algorithm reveals a novel empirical relation, fixing a limit to the energy content (therefore limits the number of cycles) of the three parts in which the authors have proposed to divide the acoustical signal.Furthermore, the realisation of multi-components phantoms, Agar and Phytagel based tissue-mimicking gels along with others long chain molecules (dextrane or polyvinyl alcohol) and scattering materials (silicon carbide and kieselguhr) are investigated.This paper reports accurate speed of sound and attenuation coefficient measurements. Speed of sound is measured by a pulse-echo technique in far-field condition, using an optical glass buffer rod; while attenuation coefficient is determined by an insertion technique, using demineralized water as reference material.The experimental sound speed results are subjected to an overall estimated relative uncertainty of about 1.5% and the attenuation coefficient uncertainty is less than 2.5%.For the development of laboratory standards, a detailed analysis of the measurement uncertainty is fundamental to make sample properties comparable. The authors believe this study could represent the right direction to make phantoms characterizations referable and traceable.

A resonance technique for the acoustic characterization of liquids in harsh environments

Accurate knowledge of a liquid's acoustic properties, such as sound speed as a function of temperature and pressure, is important for both basic and applied science. For basic science, sound speed is important for constraining thermodynamic equations-of-state as well as determining elastic nonlinearity parameters. From an applied perspective, sound speed can be used together with other properties to monitor fluid temperature, pressure, and composition. There are important applications, such as in oil/gas or geothermal well characterization, where it is desirable to measure sound speed in liquids in well bore under high pressure, high temperature, and in corrosive environments. However, few experimental sound speeds have been previously reported above 100°C even in liquids as common as water. This talk focuses on the development of a portable, rugged, resonance-based measurement cell for high precision (better than 0.1%) in-situ measurements of sound speed in high temperature, high pressure, and corrosive liquids. As an example of the technique, experimentally determined sound speeds in liquid water up to 250°C and 3000 psi will be presented. Acoustic nonlinearity in water, as determined from sound speed as a function of temperature and pressure, will also be discussed.

Evaluation of Polymer Mucoadhesiveness by the Use of Acoustic Spectroscopy

An innovative and simple methodology has been developed and used for the evaluation of mucoadhesive properties of several polymers by means of sound speed measurements using high-resolution acoustic spectroscopy. In systems made of polymers in water, variations in hydration shell of polymeric chains determine changes of dispersions compressibility, and this phenomenon can be monitored by sound speed measurements. Four different polymers have been selected, namely PEG 6000, Carbopol 974, HPMC K4M, and Pectin 200/USP, all characterised by very different mucoadhesive properties. Samples made of each polymer alone (0.3-1.0% w/w) or in mixture with mucin (mucin fixed at 1.0% w/w) in water were investigated while using high-resolution ultrasonic spectrometer at two different frequencies (5.2 and 8.2 MHz). Polymer-mucin interaction was evaluated comparing experimental sound speed values of polymer-mucin samples with their theoretical values derived from the addition of sound speeds obtained while analysing each component alone. Results demonstrated the ability of the acoustic method to discriminate between mucoadhesive and no mucoadhesive polymer-mucin dispersions and allowed also the comparison between their mucoadhesive strengths. The study has therefore demonstrated the potential of using high-resolution ultrasonic spectroscopy to evaluate the polymers' mucoadhesiveness, with the great advantage of testing small amount of samples even if opaque.

Study of a Binary Liquid Mixture of Diethylamine and 1-Decanol and Validation of Theoretical Approaches of Sound Speed at Different Temperatures

Excess parameters like excess acoustic impedance (ZE), excess internal pressure (πiE) and excess enthalpy (HE) have been calculated from measured densities (ρ), sound speed (u), and viscosities (η) of a binary mixture of diethylamine and 1-decanol at (293, 303, and 313) K over the entire range of compositions. Further, these excess parameters are fitted into the Redlich–Kister polynomial equation to find smoothing coefficients and standard error. Different theoretical models of sound speed are also applied to experimental sound speed to find the best fit theory for the system under investigation.

Experimental Sound Speeds and Derived Compressibilities of the KCl (1) + CaCl2 (2) + Water (3) and KCl (1) + MgCl2 (2) + Water (3) Systems up to an Ionic Strength of 4 mol kg-1 at 298.15 K

The experimental sound velocities of mixtures composed of KCl + CaCl2 + water and KCl + MgCl2 + water are reported at 298.15 K at several ionic strengths in the full mixture composition range. These sound velocities, in conjunction with the earlier published densities, have been employed to estimate the mean apparent molal compressibilities of the mixtures. These mean apparent molal compressibilities of the mixtures have been analyzed by the Pitzer equations without and with binary interaction parameters. The calculated properties with the help of binary interaction parameters show good agreement with those obtained from the experiments. The excess compressibilities examined in light of the Friedman equation have been correlated with excess volumes and enthalpies.

Virial equation of state and ideal-gas heat capacities of pentafluoro-dimethyl ether

A virial equation of state is presented for vapor-phase pentafluoro-dimethyl ether (CF3−O−CF2H), a candidate alternative refrigerant known as E125. The equation of state was determined from density measurements performed with a Burnett apparatus and from speed-of-sound measurements performed with an acoustical resonator. The speed-of-sound measurements spanned the ranges 260≤T≤400 K and 0.05≤P≤1.0 MPa. The Burnett measurements covered the ranges 283≤T≤373 K and 0.25≤P≤5.0 MPa. The speed-of-sound and Burnett measurements were first analyzed separately to produce two independent virial equations of state. The equation of state from the acoustical measurements reproduced the experimental sound speeds with a fractional RMS deviation of 0.0013%. The equation of state from the Burnett measurements reproduced the experimental pressures with a fractional RMS deviation of 0.012%. Finally, an equation of state was fit to both the speed-of-sound and the Burnett measurements simultaneously. The resulting equation of state reproduced the measured sound speeds with a fractional RMS deviation of 0.0018% and the measured Burnett densities with a fractional RMS deviation of 0.019%.

Speeds of Sound and Isentropic Compressibilities of Alkyl Cellosolve With Aliphatic Alcohols at 308.15K

Abstract Speeds of sound are measured in binary mixtures of alkyl cellosolve (2-ethoxyethanol and 2-butoxyethanol) with aliphatic alcohols at 308.15K. Aliphatic alcohols includes methanol, propan-1-ol, butan-1-ol, 2 methyl propan-1-ol, 2-methyl propan-2-ol and pentan-1-ol. Experimental sound speed data are used along with the density values to compute isentropic compressibilities in these mixtures. Deviations in isentropic compressibilities are negative in all the systems except in mixtures containing pentan-1-ol as non-common component, where as an inversion in sign of the function is observed. Further, speeds of sound are evaluated on the basis of Jacobson's free length theory and Schaff's collision factor theroy. The predicted values are in good agreement with the experimental results.

Speed of sound in real gases. II. Comparison with experiment

The data needed to evaluate the specific heat, virial, and relaxation corrections for the sound speed have been compiled from the literature for over 40 pure gases. Theoretical and published experimental sound speeds are compared in several case studies. (1) In precision measurements in a spherical resonator (argon, nitrogen), agreement between theory and experiment falls within 0.04% and 0.02%, respectively, over the entire ranges of temperature and pressure. (2) In high-pressure measurements (argon, helium, methane), agreement remains within 1% or better up to a certain pressure, typically 20 to 50 times the critical pressure, beyond which the increasing disagreement is attributed to truncation of the virial expansion. (3) In a measurement with large dispersion due to molecular relaxation (sulfur hexafluoride), agreement is well within 0.5%. The specific heat, virial, and relaxation corrections are analyzed in detail.

Calculated B/A parameters for n-alkane liquids

An analytic PVT equation of state, supplemented with experimental heat capacity data, was used to calculate the acoustic nonlinearity parameter B/A as a function of temperature and pressure for a series of n-alkane liquids (including polyethylene melt as a limiting case). It was found that this method generally predicts B/A values in agreement with experimental results from the literature to within the experimental uncertainty of the results, 5%. It is predicted that B/A has a maximum as a function of temperature, and this prediction is confirmed by the experimental results. A minimum as a function of pressure is also predicted and borne out by the data. The n-alkane chain length dependence of B/A is not straightforward but tends to decrease as the chain length increases. The higher-order nonlinearity parameter C/A was found to be independent of chain length.

Calculated B/A parameters for n‐alkane liquids

The B/A parameters for a series of n‐alkane liquids of chain lengths n = 5,7,8,9,12,16, and ∞ (i.e., molten polyethylene) were calculated from an analytic PVT equation of state, supplemented with experimental heat capacity data. The density, thermal expansion coefficient, sound speed, and sound‐speed derivatives (with respect to temperature and pressure) all vary in a systematic manner with chain length and approach the polyethylene values asymptotically. The pressure derivative of the sound speed is calculated much more accurately than the temperature derivative; but since the pressure derivative term dominates, the overall accuracy of the calculations is dose to the experimental accuracy. Calculated density values agree with experiment to within 0.2% while B/A values, which require a second derivative of the density, are within 5% of the values calculated numerically from experimental sound speeds in the literature.

A history of ray‐theory development at Naval Ocean Systems Center

This paper presents examples of the evolution of ray theory of underwater acoustics at the Naval Ocean Systems Center and its predecessor laboratories since 1952. The motivations for this evolution were to bring ray‐theory results into better agreement with experiments, to distinguish true acoustic properties of the ocean from artifacts resulting from the sound‐speed model or from shortcomings in ray theory, and to develop simple controls for use in evaluating complicated propagation models. Examples of such controls are the five‐parameter Epstein profile, profiles for which various ray pencils focus at a point, and closed‐form solutions for profiles with range as well as depth dependence. The most significant topics presented are the development of continuous‐gradient sound‐speed profiles, the effect of Earth's curvature and of improvements in experimental sound speeds, the application of uniform asymptotics in the boundary layer about caustics, and the development of a method using complex parameters for the evaluation of shadow‐zone fields. Various examples of ray‐theory propagation losses are compared with experiment or with the results of normal‐mode theory.This paper presents examples of the evolution of ray theory of underwater acoustics at the Naval Ocean Systems Center and its predecessor laboratories since 1952. The motivations for this evolution were to bring ray‐theory results into better agreement with experiments, to distinguish true acoustic properties of the ocean from artifacts resulting from the sound‐speed model or from shortcomings in ray theory, and to develop simple controls for use in evaluating complicated propagation models. Examples of such controls are the five‐parameter Epstein profile, profiles for which various ray pencils focus at a point, and closed‐form solutions for profiles with range as well as depth dependence. The most significant topics presented are the development of continuous‐gradient sound‐speed profiles, the effect of Earth's curvature and of improvements in experimental sound speeds, the application of uniform asymptotics in the boundary layer about caustics, and the development of a method using complex parameters fo...

Applicability of the Biot theory. II. Suspensions

The Biot theory is used to compute compressional wave speeds and attenuation in fluid–solid suspensions. The frame moduli are estimated from the self-consistent theory of composites, assuming needle-shaped pores and spherical or ellipsoidal grains of uniform size. The permeability is computed from the Kozeny–Carman equation. The attenuation data are matched by assuming that all losses are caused by viscous absorption in the fluid.For suspensions of kaolinite, polystyrene beads, and glass beads in various fluids, the Biot model agrees with experimental sound speed data at least as well as do other models. For aqueous suspensions of kaolinite, of attapulgite, and of hydrous aluminum silicate pigments, the Biot model generally is in better agreement with attenuation data than are other models.