Shear Cell Device Research Articles

Quantifying the influence of surface chemical composition on surface energy during powder flow

In this study, the dominant intermolecular interactions at powder surfaces were investigated using inverse gas chromatography. Silica beads coated with molasses, corn starch, butter, or wheat gluten were used as model powders to emulate the interactions of surface components present in common food powders. The flow properties of the powders were analyzed using a rotational shear cell device at ambient conditions (25 °C and 40% relative humidity). A positive correlation (r = 0.72, p < 0.05) between the acid-base ratio (accounting for the ratio between the number of electron acceptor to electron donor surface sites) and the flow factor (flowability indicator, ffc at 1 kPa pre-shear stress) was observed for all the size ranges of surface-modified silica beads and industry-grade powders (modified corn starch and palm oil powders). The results depict the importance of acid-base surface components in understanding the mechanistic influence of pre-load molecular dynamics on the bulk flowability.

Measurements of Interdiffusion Coefficients in Liquid AuGe Alloy

As for alloy systems forming amorphous structure, it is very useful to pursue the diffusion mechanism of the eutectic alloys in the vicinity of the eutectic point to elucidate the amorphous developmental process. We therefore investigated interdiffusion coefficients in the liquid state of AuGe and AuSi alloy, which remarkably have the deep eutectic temperature. The diffusion experiments using a shear cell device were performed in the temperature range from 686 K to 1073 K. The acquired data seem to be reliable, because they were reproducible and overlapping well on fitting curves so that the convection would have been suppressed. As a result, the temperature dependence of the interdiffusion coefficients in the liquid AuGe alloy was expressed in the Arrhenius equation and no peculiarity in the diffusion mechanism was confirmed. The values of interdiffusion coefficient of this study would be highly appropriate considering the past experimental values of self-diffusion coefficients of AuSi alloy and the negative mixing enthalpy of the alloy system. In addition, the previous research on structure analysis in which the shoulder was not observed in the vicinity of the eutectic point supported our confirmation of the Arrhenius expression for the temperature dependence of the interdiffusion coefficients in the liquid AuGe.

Lupine and rapeseed protein concentrate in fish feed: A comparative assessment of the techno-functional properties using a shear cell device and an extruder

The techno-functional properties of soy, lupine and rapeseed protein concentrates (SPC, LPC and RPC, respectively) in fish feed were evaluated relative to fish meal (FM). The effects were studied using a shear cell device and an extruder with emphasis on the added moisture content. Six diets were formulated: an SPC-based diet with 300g SPC kg−1, diets containing 100 and 200g LPC kg−1 or 100 and 200g RPC kg−1 and an FM-based diet with 450g FM kg−1. Each diet was extruded with an added moisture content of 29%, 25% and 22% of the mash feed rate. It was found that the technological properties of LPC closely resemble FM, being high solubility, low water-holding capacity (WHC) and low paste viscosity. The LPC 100 and 200gkg−1 diets could be extruded at 22% moisture, which gives an extrudate with reduced drying requirements. In addition, less specific mechanical energy was needed for extrusion. In contrast, both SPC and RPC have high WHC and paste viscosity. This explains the higher feed moisture required during extrusion. The properties of the feeds containing RPC could be well within the ranges acceptable for commercial fish feed use at even higher moisture content compared with SPC. The results of the extrusion trials confirmed the observations made from the shear cell device. Thus, the shear cell device can be used to study processing conditions that are close to extrusion conditions.

The influence of gravity on dynamic properties in sheared granular flows

The influences of gravity on the granular flow behavior and dynamic properties were experimentally studied in a vertical shear cell device where the shear dilation direction of granular materials was perpendicular to the gravity direction. The particle motions were recorded by a high-speed camera from three different observational views. By using image processing technology and the particle tracking method, the average velocities and granular temperatures in the streamwise and the transverse directions were successfully measured and analyzed. The results show that the anisotropic motions exist in sheared granular flows. The dynamic properties in the streamwise direction are larger than those in the transverse direction. Due to the gravity effect and bulk flow of granular materials, the local packing structure is not homogenous in the vertical shear cell. By comparing the three different observational views in the vertical shear cell, we find that the spatial average velocity and self-diffusion coefficient are the greatest but the shear rate and granular temperature are the smallest when the particles are co-flowing with gravity causing the most dilute packing structure due to the gravity effect. Similar experiments were also performed in a horizontal shear cell where the shear dilation direction of granular materials was against the gravity direction. The dynamic properties are smaller in the horizontal shear cell than those in the vertical shear cell. It is because the horizontal shear cell has the smaller shear rate with the shear dilation direction against the gravity direction.

Experimental analysis of dynamic properties in wet sheared granular matter

We performed experiments to measure the dynamic properties of wet granular matter in a shear cell device. The purpose was to quantify the effect of the liquid bridge force on granular systems. The motions of the granular materials were recorded by a high-speed camera. Image processing technology and particle tracking method were employed to measure the velocities, fluctuation velocities and granular temperatures in the streamwise and the transverse directions. The results show that adding small amounts of liquid with different viscosities, and changing the wall velocity, both have significant influences on the dynamic properties of wet granular matter due to the formation and rupturing of liquid bridges. The energy dissipation due to the formation and rupturing of the liquid bridges increases with the increase of wall velocity and the increase of liquid viscosity. The effect of the liquid bridge force on the dynamic properties is not only dependent on the liquid viscosity but also on the kinetic energy of the granular system.

Mixing of cohesive particles in a shear cell

This paper discusses two series of experiments performed in a shear cell device with six different amounts of silicone oils and using 2-mm soda lime beads as the granular materials. The first series of experiments were mixing experiments, and the developments of mixing layer thicknesses were measured. The second series of experiments had the same experimental conditions as the first series but used different combinations of colored particles. In the second series of experiments, the motions of granular materials were recorded by a high-speed camera. Using the image processing technology and particle tracking method, the positions and velocities of particles were measured. The self-diffusion coefficient could be found from the history of the particle displacements. The measured mixing layer thicknesses are compared with the calculations from a simple diffusion equation using the data of apparent self-diffusion coefficients obtained from the current measurements. The comparisons show good agreements, demonstrating that the mixing process of granular materials occur through the diffusion mechanism in this cohesive sheared flow. In addition, the apparent self-diffusion coefficient decreases with the increasing liquid volume, indicating that cohesive effect between particles reduces granular mixing.

The effect of liquid viscosity on sheared granular flows

This work investigates the effect of transport properties in sheared granular flows with adding different silicone oils. We performed a series of experiments in a shear cell device using 2-mm soda lime beads as the granular materials by adding little amount of different silicone oils. The viscosity of silicone oils added was changed in different tests. By particle tracking method, the velocities, the velocity fluctuations and the self-diffusion coefficients were measured and analyzed. It was found that for the granular system with adding the more viscous silicone oil, the system became less active due to the greater shear force and cohesive force, which resulted in the decrease of velocity fluctuations and diffusions. Three bi-directional stress gages were installed to the upper wall to measure the normal and shear stresses of the granular materials along the upper wall. Thus, the effective viscosities of the wet granular material systems could be evaluated. The dimensionless normal and shear stresses, and the effective viscosity in the wet sheared granular flow were found to decrease with the increase of the viscosity of the added silicone oil. The influence of the viscosity of added fluid on these transport properties of wet granular systems will be discussed.

Particle mixing in a sheared granular flow

Mixing experiments were performed in a shear cell device using differently colored but otherwise identical glass spheres, with five different bottom wall velocities. The motions of the granular materials were recorded by a high-speed camera, so the development of mixing boundaries could be analyzed from the images. By continually tracking the movements of particles, the velocity, fluctuations and the granular temperatures were measured. The self-diffusion coefficients were determined from the histories of particles movements. The mixing layer thicknesses were compared with the calculations from a simple diffusion equation using the data of self-diffusion coefficients obtained from the current measurements. The calculations and experimental results showed good agreements, demonstrating that the mixing process of granular materials occurred through the diffusion mechanism.

Wet granular materials in sheared flows

The transport properties of wet granular materials in a shear cell apparatus have been studied. If the particles are wet, the flow becomes more viscous forming liquid bridges between particles. The dynamic liquid bridge forces are considered as the cohesive forces between particles to restrict their movements. The cohesive forces make the particles stick tighter with each other and hamper the movement of particles. The mixing and transport properties are influenced seriously by the amount of moisture added in the flow. This paper discusses a series of experiments performed in a shear cell device with five different moisture contents using 3-mm glass spheres as the granular materials. The motion of granular materials was recorded by a high-speed camera. Using the image processing technology and particle tracking method, the average and fluctuation velocities in the streamwise and transverse directions could be measured. The self-diffusion coefficient could be found from the history of the particle displacements. The self-diffusion coefficients and fluctuations in the streamwise direction were much larger than those in the transverse direction. Three bi-directional stress gages were installed to the upper wall to measure the normal and shear stresses of the granular materials along the upper wall. For wetter granular material flows, the fluctuation velocities and the self-diffusion coefficients were smaller.

Transport property measurements in sheared granular flows

Experiments were performed in a shear cell device under four different solid fractions. The glass spheres with a mean diameter of 3 mm were used as granular materials. The motions of the granular materials were recorded by a high-speed camera. By using image processing technology and a particle tracking method, the average and fluctuation velocities in the streamwise and the transverse directions could be successfully measured and analyzed. Three bi-directional stress gages were used to measure the normal and shear stresses along the upper boundary. The effective viscosity of the granular material flow can be calculated. By tracking the movements of particles continually, the curves of the mean-square diffusive displacements versus time were plotted and were used to determine the self-diffusion coefficients from the slopes of the curves. The fluctuations and the self-diffusion coefficients in the streamwise direction were much higher than those in the transverse direction. The fluctuations were found to increase with the solid fraction, but the diffusion coefficients were greater in a more dilute flow system.

Stresses and transport phenomena in sheared granular flows with different wall conditions

Experiments were performed in a shear cell device with four different wall conditions. The glass spheres with a mean diameter of 3 mm were used as granular materials. Three bidirectional stress gauges were installed to measure the normal and shear stresses along the upper wall. The motions of the granular materials were recorded by a high-speed camera. The image processing technology and particle tracking method were employed to measure the average and fluctuation velocities in the streamwise and the transverse directions. By tracking the movements of particles continually, the variation in the mean-square diffusive displacements with time was plotted and the self-diffusion coefficient was determined. The self-diffusion coefficients in the streamwise direction were much higher than those in the transverse direction. The self-diffusion coefficients were increased with the increase of the velocity fluctuations, the shear rates, and the stresses. The influences of the wall conditions (wall frictional coefficients) on these properties are discussed in the paper.

Effect of solid fraction on fluctuations and self-diffusion of sheared granular flows

The influences of solid fraction on the fluctuations and self-diffusion of sheared granular flows were experimentally studied in a shear cell device. Employing the image processing technology and particle tracking method, the local displacements and velocities of particles were measured. From the measured velocities, the fluctuations, granular temperatures and shear rates could be determined. The self-diffusion coefficients were determined from the history of particles’ diffusive displacements. The periodic cell concept was used for long-time tracking purpose. Because of the gravitation force, the flows consist of both a solid-like region with higher and more uniform velocities in the lower test section and a fluid-like region in the upper part. The velocity fluctuations and self-diffusions were anisotropic with greatest components in the streamwise direction. The flow rheology was very sensitive to the mean solid fraction of the granular flow. The dependence of the diffusion coefficients on the velocity fluctuations and the shear rate were discussed.

Fluctuations and self-diffusion of sheared granular material flows

Experiments were performed in a shear cell device with adjustable lower wall velocity. Glass spheres with a mean diameter of 3 mm were used as granular materials. Image processing technology and a particle tracking method were employed to measure the average and fluctuation velocities in the streamwise and the transverse directions. Because of gravitation force, the flows consist of both a solid-like region with higher and more uniform velocities in the lower test section and a fluid-like region in the upper part. The velocity fluctuations were anisotropic and were greater in the streamwise direction. By tracking the movements of particles continually, the variation in the mean-square diffusive displacements with time was plotted and the self-diffusion coefficient was determined. The self-diffusion coefficients in the streamwise direction were much higher than those in the transverse direction. The dependence of the diffusion coefficients on the velocity fluctuations and the shear rate were discussed.

Diffusion coefficients ofSb124,Sn113,Ag110m, andAu195in liquid copper

Measurements of the diffusion coefficient of $^{124}\mathrm{Sb}$, $^{113}\mathrm{Sn}$, $^{110m}\mathrm{Ag}$, and $^{195}\mathrm{Au}$ in liquid copper are made using a shear-cell device which provides accurate data. The experimental diffusion coefficient is given by ${D}_{i}=C{D}_{i}^{E}$, where ${D}_{i}^{E}$ is obtained using Enskog's theory and $C$ is a correction factor accounting for dynamical correlation effects. $C$ is a function of the fluid density and of the relative mass and size of the solute with respect to the solvent. The data show that among the solutes smaller in size and mass than the solvent, those of larger mass and smaller size tend to diffuse more rapidly than predicted by Enskog's theory. For solutes larger and heavier than the solvent, the diffusion coefficient tends to increase with their mass and size.

Electrodiffusion and electroconvection inSnIn andSnSb dilute liquid alloys

The effective diffusion coefficient ${D}_{\mathrm{eff}}$ and the apparent effective valence ${Z}^{**}$ of In and Sb as dilute impurities in liquid Sn have been measured using a shear cell device. ${D}_{\mathrm{eff}}$ is shown to vary quadratically as a function of the current density $j(A{\mathrm{cm}}^{\ensuremath{-}2})$ ${D}_{\mathrm{eff}}^{\mathrm{In}}=4.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}+1.22\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}{j}^{2}$ (${\mathrm{cm}}^{2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$). A possible origin of the electroconvective enhancement of the diffusion coefficient is discussed. The effective valences ${Z}_{\mathrm{In}}^{**}=+1.4\ifmmode\pm\else\textpm\fi{}0.9$; ${Z}_{\mathrm{Sb}}^{**}=\ensuremath{-}4.2\ifmmode\pm\else\textpm\fi{}4$ are in good agreement with theoretical calculations.

Experimental measuremnet of the diffusion coefficient of ag110m, cd109, in114m, sn113and sb125in liquid tin

Abstract We describe a precise method for measuring the diffusion coefficient of solutes in liquid metals. A thin layer of a radioactive isotope of the solute is allowed to diffuse in capillaries which can be sectioned using a shear cell device. This method allows a precise measurement of the temperature and of the time duration of the experiment, and avoids any solute segregation when cooling the samples. The experimental results show that there is a negligible direct influence of the valence of a solute on its diffusion coefficient in tin