Hard sphere colloidal dispersions: Viscosity as a function of shear rate and volume fraction

1985 ◽  
Vol 83 (9) ◽  
pp. 4717-4725 ◽  
Author(s):  
C. G. de Kruif ◽  
E. M. F. van Iersel ◽  
A. Vrij ◽  
W. B. Russel
Keyword(s):  
Shear Rate ◽  
Hard Sphere ◽  
Volume Fraction ◽  
Colloidal Dispersions

scholarly journals Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

2021 ◽  
Author(s):  
Patrick Wilms ◽  
Jan Wieringa ◽  
Theo Blijdenstein ◽  
Kees van Malssen ◽  
Reinhard Kohlus
Keyword(s):  
Shear Stress ◽  
Liquid Phase ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Slip Velocity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Wall Slip ◽  
Flow Index ◽  
Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

Rheological Characteristics of Viscoelastic Surfactant Fluid Mixed With Silica Nanoparticles

2013 ◽  
Author(s):  
Yueqiong Wu ◽  
Zhongyang Luo ◽  
Hong Yin ◽  
Tao Wang
Keyword(s):  
High Temperature ◽  
Shear Rate ◽  
Volume Fraction ◽  
Sio2 Nanoparticles ◽  
Fluid Loss ◽  
Rheological Characteristics ◽  
High Shear ◽  
Fracturing Process ◽  
Viscoelastic Surfactant ◽  
Rheological Performance

Since the surfactant can form rod-like micelles or even cross-link structures, viscoelastic surfactant (VES) fluid has unique rheological characteristics. The demerits of VES fluids have been proven after being applied as the fracturing fluid for several years. However, the fluid has high fluid loss and a low viscosity at high temperature, which limits the application to hydraulic fracturing. This paper focuses on the VES fluid mixed with nanoparticles which should be an effective way to maintain the viscosity at high temperature and high shear rate. The experiments were based on preparation of uniform and stable nanocolloids, which utilize Microfluidizer high shear fluid processor. Dynamic light scattering and microscopic methods are employed to investigate the stability and micro-structure of the VES fluid. The effects of temperature, shear rate and volume fraction of the nanoparticles on rheology of VES were studied. The SiO2 nanoparticles could significantly improve the rheological performance of VES fluid, although the rheological performance at the temperature over 90 °C needs to be enhanced. The mechanisms of interactions between nanoparticles and micelles are also discussed later in the paper. At the end, the potential of VES fluid mixed with nanoparticles during application in fracturing process was discussed.

New bounds on the sedimentation velocity for hard, charged and adhesive hard-sphere colloids

2011 ◽  
Vol 667 ◽  
pp. 403-425 ◽  
Author(s):  
W. TODD GILLELAND ◽  
SALVATORE TORQUATO ◽  
WILLIAM B. RUSSEL
Keyword(s):  
Brownian Motion ◽  
Upper Bound ◽  
Hard Sphere ◽  
Large Scale ◽  
Hard Spheres ◽  
Colloidal Dispersions ◽  
Sedimentation Velocity ◽  
Close Packing ◽  
Interparticle Potential ◽  
Equilibrium Microstructure

The sedimentation velocity of colloidal dispersions is known from experiment and theory at dilute concentrations to be quite sensitive to the interparticle potential with attractions/repulsions increasing/decreasing the rate significantly at intermediate volume fractions. Since the differences necessarily disappear at close packing, this implies a substantial maximum in the rate for attractions. This paper describes the derivation of a robust upper bound on the velocity that reflects these trends quantitatively and motivates wider application of a simple theory formulated for hard spheres. The treatment pertains to sedimentation velocities slow enough that Brownian motion sustains an equilibrium microstructure without large-scale inhomogeneities in density.

Heat transfer and shear-induced migration in dense non-Brownian suspension flows: modelling and simulation

2018 ◽  
Vol 840 ◽  
pp. 432-454 ◽  
Author(s):  
T. Dbouk
Keyword(s):  
Heat Transfer ◽  
Thermal Diffusivity ◽  
Shear Rate ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Laminar Flows ◽  
Modelling And Simulation ◽  
Particle Migration ◽  
Concentrated Suspension ◽  
Suspension Flows

Modelling and simulation are developed, generalized and validated for both heat transfer and shear-induced particle migration in dense non-colloidal laminar suspension flows. Past theory and measurements for the effective thermal conductivity in porous materials at zero shear rate are coupled to more recent effective thermal diffusivity measurements of sheared suspensions. The suspension effective heat transfer affected by the local shear rate ($\dot{\unicode[STIX]{x1D6FE}}$), the phenomenon of shear-induced particle migration (SIM), the buoyancy effects ($\unicode[STIX]{x0394}\unicode[STIX]{x1D70C}$) and the thermal Péclet number ($Pe_{d_{p}}=\dot{\unicode[STIX]{x1D6FE}}d_{p}^{2}/\unicode[STIX]{x1D6FC}_{f}$, where $d_{p}$ is the diameter of rigid particles and $\unicode[STIX]{x1D6FC}_{f}$ is the fluid phase thermal diffusivity) at the particle scale are all considered in the present constitutive three-dimensional modelling. Moreover, the influence of the temperature, the shear rate and the particle volume fraction ($\unicode[STIX]{x1D719}$) on the suspension effective viscosity ($\unicode[STIX]{x1D702}_{S}$), the suspension effective thermal properties and the fluid density ($\unicode[STIX]{x1D70C}_{f}$) are taken also into account. The present contribution represents an emerging field of heat transfer applications of complex fluid flows and is very beneficial for many future applications where concentrated suspension laminar flows with conjugate heat transfer may be present (e.g. for designing more innovative and compact heat exchangers).

Flow instability due to coupling of shear-gradients with concentration: non-uniform flow of (hard-sphere) glasses

Soft Matter ◽  
2014 ◽  
Vol 10 (47) ◽  
pp. 9470-9485 ◽  
Author(s):  
Howon Jin ◽  
Kyongok Kang ◽  
Kyung Hyun Ahn ◽  
Jan K. G. Dhont
Keyword(s):  
Shear Rate ◽  
Hard Sphere ◽  
Flow Instability ◽  
Microscopic Theory ◽  
Shear Rates ◽  
Spatial Gradients ◽  
Flow Profiles ◽  
Mass Fluxes ◽  
Glassy Systems ◽  
Low Shear

A microscopic theory explains the origin of mass fluxes induced by spatial gradients in the shear rate, and leads to an expression for the corresponding transport coefficient. The resulting instability gives rise to banded flow profiles in glassy systems for low shear rates.

Rheological Behavior of Semisolid Al-6.5wt%Si Alloy under Cyclic Shear Deformation

2011 ◽  
Vol 306-307 ◽  
pp. 104-107
Author(s):  
Hong Chao Luo ◽  
Jun Mei Yang ◽  
Li Yuan Sun ◽  
Li Ping Ju
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Hysteresis Loop ◽  
Shear Deformation ◽  
Rheological Behavior ◽  
Qualitative Agreement ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Cyclic Shear ◽  
The Difference

In the present work, the MCF model for semisolid metal slurries (SSMS) is applied to investigate the thixotropy of the Al-6.5wt%Si alloy under cyclic shear deformation. The study shows that the semisolid Al-6.5wt%Si alloy has the behavior of thixotropy. The area of the hysteresis loop increases with decreasing the up-time, the initial shear rate and increasing resting time, solid volume fraction and maximum shear rate, respectively. These results have qualitative agreement with the experimental data. The origin of the hysteresis loop is atrributed to the difference between the deagglomeration rate and the agglomeration rate.

Adhesive hard-sphere colloidal dispersions. A small-angle neutron-scattering study of stickiness and the structure factor

Langmuir ◽  
1989 ◽  
Vol 5 (2) ◽  
pp. 422-428 ◽  
Author(s):  
C. G. De Kruif ◽  
P. W. Rouw ◽  
W. J. Briels ◽  
M. H. G. Duits ◽  
A. Vrij ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Structure Factor ◽  
Hard Sphere ◽  
Small Angle Neutron Scattering ◽  
Colloidal Dispersions ◽  
Scattering Study ◽  
Neutron Scattering Study

Adhesive hard-sphere colloidal dispersions III. stickiness in n-dodecane and benzene

1988 ◽  
Vol 31 ◽  
pp. 299-309 ◽  
Author(s):  
P.W. Rouw ◽  
A. Vrij ◽  
C.G. De Kruif
Keyword(s):  
Hard Sphere ◽  
Colloidal Dispersions
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