Characterisation of colloidal dispersions using ultrasound spectroscopy and multiple-scattering theory inclusive of shear-wave effects

Forrester, Derek Michael; Huang, Jinrui; Pinfield, Valerie J.

doi:10.1016/j.cherd.2016.08.008

Cited by 20 publications

(12 citation statements)

References 36 publications

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“…This is consistent with previous observations of a similar behavior of the coherent wave effective properties made during the comparison of a multi-mode multiple scattering model with experimental data. [41][42][43] The analytical results presented account for viscous effects in modelling the dynamics of nanoparticle systems. We chose to follow the same procedure as the authors of Ref.…”

Section: Discussionmentioning

confidence: 99%

“…Recent numerical investigation by Pinfield's group 41 and experimental validation (on acoustic attenuation) 42,43 have demonstrated that the resonance peak observed in the attenuation against frequency curve for the coherent compressional wave also shifts to higher Reðk s aÞ as the concentration increases. This is consistent with the findings here on the effect of concentration on the effective density, which influences the effective compressional wavenumber.…”

Section: B Dependence On Frequency At Different Concentrationsmentioning

confidence: 99%

“…The previously neglected multi-mode conversions have been demonstrated to be significant in nanoparticle suspensions and the new model applied to such systems 41 presents a greatly improved agreement with experimental data. 42,43 Further experimental evidence of the FIG. 1.…”

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confidence: 96%

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Effective dynamic properties of random complex media with spherical particles

Alam

Pinfield

Luppé

et al. 2019

The Journal of the Acoustical Society of America

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The effective dynamic bulk modulus and density are presented for random media consisting of particles in a viscous host fluid, using a core-shell, self-consistent effective medium model, under the large compressional wavelength assumption. These properties are relevant to acoustic or dynamic processes in nano-and micro-particle fluids including particle density determination, resonant acoustic mixing, and acoustic characterisation. Analytical expressions are obtained for the effective bulk modulus and mass density, incorporating the viscous nature of the fluid host into the core-shell model through wave mode conversion phenomena. The effective density is derived in terms of particle concentration, particle and host densities, particle size, and the acoustic and shear wavenumbers of the liquid host. The analytical expressions obtained agree with prior known results in the limit of both static and inviscid cases; the ratio of the effective bulk modulus to that of the fluid is found to be quasi-static. Numerical calculations demonstrate the dependence of the effective mass density on frequency, particle size (from nano-to micro-regime), and concentration. Herein it is demonstrated both theoretically and numerically that the viscosity, often neglected in the literature, indeed plays a significant role in the effective properties of nanofluids.

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Section: Discussionmentioning

confidence: 99%

Section: B Dependence On Frequency At Different Concentrationsmentioning

confidence: 99%

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Effective dynamic properties of random complex media with spherical particles

Alam

Pinfield

Luppé

et al. 2019

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

show abstract

“…This corresponds to a shear wave resonance where the shear wavelength is comparable to the particle size. In suspensions in which particles are on average closer together than the viscous decay length, the shear wave field influences neighbouring particles, modifying the scattered acoustic field, resulting in a reduction in the energy lost in viscous dissipation 6 . This is similar to a Schlichting boundary layer becoming as large as the gap between two surfaces.…”

Section: Discussionmentioning

confidence: 99%

Modelling viscous boundary layer dissipation effects in liquid surrounding individual solid nano and micro-particles in an ultrasonic field

Forrester

Huang

Pinfield

2019

Sci Rep

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Upon application of ultrasonic waves to a suspension of solid particles in liquid, multiple scattering occurs at the particle/liquid interfaces leading to attenuation. It was recently shown through experimental verification that multiple scattering theory must include shear wave influences at the boundary between the liquid and solid particles in a nanofluid when the concentration of the scatterers is even as low as a few percent by volume. Herein, we consider silica spheres of 50–450 nm diameter in the long-wavelength regime to elucidate the form of the shear decay fields at the liquid/solid interface for individual particles. This is important because the overlap of these fields ultimately leads to the conversion of a compressional wave to shear waves and back into the compressional wave, the effect originating due to the density contrast between the particle and the liquid. Therefore, we examine in detail the velocity, vorticity and viscous dissipation in the shear wave field and around the silica spheres using finite element modelling, giving clarity to the viscous boundary effects. We also compare the numerical modelling to semi-analytical results.

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“…In heterogeneous systems, interpretation of acoustic spectra is more complex and remains an open question. In controlled suspensions, measured attenuations [17][18][19] can be described by rigorous yet sophisticated models [20][21][22][23][24][25][26] or by more empirical approaches [27,28] but such modeling is still out of reach for more complex industrial systems. For instance, some studies were devoted to sound attenuation in biomedical [29][30][31], pharmaceutical [32,33] or food samples [34][35][36][37], but they remain mostly qualitative and do not attempt to model acoustic signals.…”

Section: Introductionmentioning

confidence: 99%

Acoustic monitoring of the gelation of a colloidal suspension

Bélicard¹,

Niémet-Mabiala²,

Tourvieille³

et al. 2022

Preprint

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Because they are sensitive to mechanical properties of materials and can propagate even in opaque systems, acoustic waves provides us with a powerful characterization tool in numerous fields. Common techniques mostly rely on time-of-flight measurements and do not exploit the spectral content: however, sound speed and attenuation spectra contain rich information. Such an acoustic spectroscopy already exists and allows to retrieve subtle information on systems of well-known physico-chemistry, but modeling becomes out of reach for industrial systems. In this article, we use a simple empirical approach to monitor the gelation of silica suspensions: we show that the gelation time obtained from acoustic measurements is proportional to this determined with more conventional rheological characterization. Such a results thus opens the way for in-situ monitoring of time-evolving systems in industrial context with acoustic methods only.

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Characterisation of colloidal dispersions using ultrasound spectroscopy and multiple-scattering theory inclusive of shear-wave effects

Cited by 20 publications

References 36 publications

Effective dynamic properties of random complex media with spherical particles

Effective dynamic properties of random complex media with spherical particles

Modelling viscous boundary layer dissipation effects in liquid surrounding individual solid nano and micro-particles in an ultrasonic field

Acoustic monitoring of the gelation of a colloidal suspension

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