Transport and Capture of Colloidal Particles in Single Fractures

1984 ◽  
Vol 44 ◽  
Author(s):  
E. J. Bonano ◽  
W. E. Beyeler
Keyword(s):  
Particle Velocity ◽  
Colloidal Particles ◽  
Particle Production ◽  
Dynamic Balance ◽  
Fluid Velocity ◽  
Single Fracture ◽  
Average Particle ◽  
Particle Capture ◽  
External Forces ◽  
Plate Channel

AbstractIn this study, the transport and capture rates of colloidal particles were calculated for a parallel-plate channel simulating a single fracture. The steady-state convective diffusion equation was solved with the particle velocity normal to the walls of the channel being the sum of the external forces acting on the particles. The forces considered were the gravitational, London-van der Waals and electric-double layer forces. The effects of parameters governing these forces and particle production mechanism on the rates of particle capture and transport are determined. The dynamic balance between particle production and capture has a significant effect on the concentration of particles leaving the fracture. The average particle velocity, though higher than the average fluid velocity, seems to be insensitive to phenomena governing particle capture.

scholarly journals Sedimentation of a dilute suspension of rigid spheres at intermediate Galileo numbers: the effect of clustering upon the particle motion

2014 ◽  
Vol 752 ◽  
pp. 310-348 ◽  
Author(s):  
Markus Uhlmann ◽  
Todor Doychev
Keyword(s):  
Particle Velocity ◽  
Settling Velocity ◽  
Fluid Velocity ◽  
Voronoi Tessellation ◽  
Density Ratio ◽  
Fluid Motion ◽  
Finite Size ◽  
Vertical Motion ◽  
Average Particle ◽  
Rigid Spheres

AbstractDirect numerical simulation of the gravity-induced settling of finite-size particles in triply periodic domains has been performed under dilute conditions. For a single solid-to-fluid-density ratio of 1.5 we have considered two values of the Galileo number corresponding to steady vertical motion ($\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}\mathit{Ga}=121$) and to steady oblique motion ($\mathit{Ga}=178$) in the case of one isolated sphere. For the multiparticle system we observe strong particle clustering only in the latter case. The geometry and time scales related to clustering are determined from Voronoï tessellation and particle-conditioned averaging. As a consequence of clustering, the average particle settling velocity is increased by 12 % as compared with the value of an isolated sphere; such a collective effect is not observed in the non-clustering case. By defining a local (instantaneous) fluid velocity average in the vicinity of the finite-size particles it is shown that the observed enhancement of the settling velocity is due to the fact that the downward fluid motion (with respect to the global average) which is induced in the cluster regions is preferentially sampled by the particles. It is further observed that the variance of the particle velocity is strongly enhanced in the clustering case. With the aid of a decomposition of the particle velocity it is shown that this increase is due to enhanced fluid velocity fluctuations (due to clustering) in the vicinity of the particles. Finally, we discuss a possible explanation for the observation of a critical Galileo number marking the onset of clustering under dilute conditions.

scholarly journals Myosin II heavy chain null mutant of Dictyostelium exhibits defective intracellular particle movement.

1990 ◽  
Vol 111 (3) ◽  
pp. 1137-1148 ◽  
Author(s):  
D Wessels ◽  
D R Soll
Keyword(s):  
Particle Velocity ◽  
Heavy Chain ◽  
Peak Concentration ◽  
Myosin Ii ◽  
Computer Assisted ◽  
Average Particle ◽  
Cellular Motility ◽  
Null Mutant ◽  
Particle Movement ◽  
Dynamic Morphology

Both cellular motility and intracellular particle movement are compared between normal Dictyostelium amebae of strain AX4 and amebae of a myosin II heavy chain null mutant, HS2215, using the computer assisted "Dynamic Morphology System." In AX4 cells rapidly translocating in buffer, cytoplasmic expansion is apical and the majority of intracellular particles move anteriorly, towards the site of expansion. When these cells are pulsed with 10(-6) M cAMP, the peak concentration of the natural cAMP wave, cells stop translocating and average particle velocity decreases threefold within 2-4 s after cAMP addition. After 8 s, there is a partial rebound both in cytoplasmic expansion and particle velocity, but in both cases, original apical polarity is lost. In HS2215 cells in buffer, both cellular translocation and average particle velocity are already at the depressed levels observed in normal cells immediately after cAMP addition, and no anterior bias is observed in either the direction of cytoplasmic expansion or the direction of particle movement. The addition of cAMP to myosin-minus cells results in no additional effect. The results demonstrate that myosin II is necessary for (a) the rapid rate of intracellular particle movement, (b) the biased anterior directionality of particle movement, and (c) the rapid inhibition of particle movement by cAMP.

scholarly journals Average particle velocity in solid-liquid two-phase flow through vertical and horizontal tubes.

1980 ◽  
Vol 13 (5) ◽  
pp. 343-349 ◽  
Author(s):  
HIROYASU OHASHI ◽  
TAKUO SUGAWARA ◽  
KEN-ICHI KIKUCHI ◽  
MICHIHITO ISE
Keyword(s):  
Particle Velocity ◽  
Two Phase Flow ◽  
Average Particle ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Tubes ◽  
Flow Through ◽  
Solid Liquid

scholarly journals The Promotion/Inhibition of the Seepage Transport of Copper Ions by Suspension-Colloidal Particles with Wide Size Gradation

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qingke Nie ◽  
Huawei Li ◽  
Haipeng Yang ◽  
Tengfei Ni ◽  
Sichen Jiang
Keyword(s):  
Heavy Metal ◽  
Particle Size ◽  
Large Scale ◽  
Colloidal Particles ◽  
Copper Ions ◽  
Small Scale ◽  
Average Particle ◽  
Promoting Effect ◽  
Transport Distance ◽  
Retarding Effect

Sand column tests were conducted to investigate the seepage transport of silicon powders (SPs) with two wide particle size ranges (30-2000 nm and 2-70 μm), including the cotransport of SPs and copper ions. The results show that the graded large-scale SP has an obvious inhibiting influence on the transport of copper ions. In contrast, in the presence of the graded small-scale SP, the concentration of copper ions in the effluent tends to increase; i.e., there appears to be a promoting effect. However, after a long transport distance, the presence of SPs, regardless of particle size, has an overall retarding effect on heavy metal pollutants (e.g., copper ions). The promoting effect of the increase in seepage velocity on the concentration of copper ions in the effluent is greater with the graded large-scale SPs than with the graded small-scale SPs. In terms of the microstructural characteristics by metallographic microscopy, the average particle size of the deposited graded small-scale SPs is almost constant at different transport distances, while that of the deposited graded large-scale SPs tend to decrease significantly with increasing transport distance; i.e., notable bed filtration is exhibited in the latter case. This physical mechanism also determines the sequence and rate of the retarding effect of SPs on heavy metal ions under seepage flow.

scholarly journals Preparation and Investigation of Intelligent Polymeric Nanocapsule for Enhanced Oil Recovery

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1093 ◽  
Author(s):  
Fang Shi ◽  
Jingchun Wu ◽  
Bo Zhao
Keyword(s):  
Particle Size ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Colloidal Particles ◽  
Critical Concentration ◽  
Average Particle Size ◽  
Average Particle ◽  
Assembly Method ◽  
Recovery Capacity ◽  
Wide Range

Micro-/nanomotors colloidal particles have attracted increasing interest as composite surfactants, owing to the combined advantages of both Janus solid surfactants and micro-/nanomotors. Here we put micro-/nanomotors colloidal particles into hollow polymeric micro-encapsulates. An intelligent polymeric nanocapsule was prepared for enhanced oil recovery by the self-assembly method. The particle size range of the polymeric capsule can be controlled between 20 to 1000 nm by adjusting the cross-linking thickness of the capsule’s outer membrane. The average particle size of polymeric capsules prepared in the study was 300 nm. The structure and properties of the Intelligent polymeric nanocapsule was characterized by a wide range of technics such as Fourier transform infrared spectroscopy, scanning electron microscopy by laser diffraction, fluorescence microscopy, pendant drop tensiometer, laser particle size instrument, and interface tension analyzer. It was found that the intelligent polymeric nanocapsule exhibited significant interfacial activity at the oil-water interface. When the Janus particles’ concentration reached saturation concentration, the adsorption of the amphiphilic nanoparticles at the interface was saturated, and the equilibrium surface tension dropped to around 31 mN/m. When the particles’ concentration reached a critical concentration of aggregation, the Gibbs stability criterion was fulfilled. The intelligent polymeric nanocapsule system has a better plugging and enhanced oil recovery capacity. The results obtained provide fundamental insights into the understanding of the assembly behavior and emulsifying properties of the intelligent polymeric nanocapsule, and further demonstrate the future potential of the intelligent polymeric nanocapsule used as colloid surfactants for enhanced oil recovery applications.

Visualization of Heat Transfer Characteristics of 1EHT and Smooth Surface Tubes

2021 ◽  
Author(s):  
Humberto Santos ◽  
Ailson Alves ◽  
David Kukulka ◽  
Rick Smith ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Particle Velocity ◽  
High Speed ◽  
High Efficiency ◽  
Bubble Formation ◽  
Industrial Applications ◽  
Smooth Tube ◽  
Outer Diameter ◽  
Average Particle ◽  
Enhanced Heat Transfer

Abstract High efficiency heat transfer tubes play a major role in industrial applications due to its benefits in recovering more energy, smaller footprint and lower operational costs. Given the importance of enhanced heat transfer tubes, an experimental investigation was carried out to compare the performance of the Vipertex 1EHT tube with an equivalent smooth tube using Particle Image Velocimetry (PIV). For the experimental setup a Dantec Dynamics PIV system was considered, and both tubes used had an outer diameter of 19.05 mm and inner diameter of 17.09 mm. Heat transfer experiments were conducted at 100% of the heater power capacity, i.e. 750 W, and observations were made in terms of boiling visualization, particle velocity vector field, and seeding particle velocity. The results obtained from the visualization showed higher density of bubble formation on the surface of 1EHT tube compared to the smooth tube, as well as a more frequent formation of bubbles. Moreover, the high-speed camera films recorded for comparison between smooth and enhanced tubes, showed that the dimples provided nucleation sites. Additionally, the average particle velocity for the 1EHT tube was 0.300 m.s−1 and for the smooth tube it was only 0.230 m.s−1, as a result of the higher heat transfer of the enhanced tube. These results suggest that the 1EHT tube performs better in boiling heat transfer application, which can be attributed to the enhanced heat transfer area produced by the series of dimples/protrusions and petals distributed over its surface.

Drag Coefficient and Settling Velocity of Particles in Non-Newtonian Suspensions

1987 ◽  
Vol 109 (3) ◽  
pp. 319-323 ◽  
Author(s):  
M. Y. Dedegil
Keyword(s):  
Reynolds Number ◽  
Shear Stress ◽  
Drag Coefficient ◽  
Yield Stress ◽  
Particle Velocity ◽  
Settling Velocity ◽  
Fluid Velocity ◽  
Newtonian Fluids ◽  
Drag Forces ◽  
Physical Composition

Drag forces on bodies in non-Newtonian fluids which are to be described by using the Reynolds number should only contain forces which are associated with the fluid velocity or particle velocity. Forces due to the yield stress τ0 must be considered separately. According to its physical composition, the Reynolds number must be calculated by means of the fully representative shear stress including the yield stress τ0. Then the drag coefficient cD as a function of the Reynolds number can be traced back to that of Newtonian fluids.

High-Speed Shadowgraphy Measurements of an Erosive Particle-Laden Jet Under High-Pressure Compressor Conditions

2017 ◽  
Author(s):  
M. Hufnagel ◽  
C. Koch ◽  
S. Staudacher ◽  
C. Werner-Spatz
Keyword(s):  
Dimensional Analysis ◽  
Particle Velocity ◽  
High Speed ◽  
Fluid Velocity ◽  
Measurement Techniques ◽  
Real Life ◽  
Negative Influence ◽  
Solid Particles ◽  
Flat Plates ◽  
Aerodynamic Properties

Erosive damage done to jet engine compressor blading by solid particles has a negative influence on the compressor aerodynamic properties and hence decreases performance. The erosive change of shape has been investigated in a multitude of experiments ranging from eroding flat plates to eroding full engines. The basic challenge to transfer the results from very simple tests to real life erosion remains. Up to date measurement techniques today allow closing this gap. The necessary experimental and analytical steps are shown. The erosion resistance of Ti-6Al-4V at realistic flow conditions with fluid velocities ranging from 200 to 400 m/s is used. The erodent used was quartz sand with a size distribution corresponding to standardized Arizona Test Dust A3 (1 to 120 μm). Flat plates out of Ti-6Al-4V were eroded at different impingement angles. The particle velocities and sizes were investigated using a high speed laser shadowgraphy technique. A dimensional analysis was carried out to obtain nondimensional parameters suitable for describing erosion. Different averaging methods of the particle velocity were examined in order to identify a representative particle velocity. Compared to the fluid velocity and the mean particle velocity, the energy averaged particle velocity is found to be the best representation of the erosiveness of a particle stream. The correlations derived from the dimensional analysis are capable of precisely predicting erosion rates for different rig operating points. The results can be applied to the methodology published in [1].

Particle Velocities in the Rotating Impeller of a Slurry Pump

2007 ◽  
Author(s):  
M. Mehta ◽  
J. R. Kadambi ◽  
S. Sastry ◽  
J. M. Sankovic ◽  
M. P. Wernet ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Particle Velocity ◽  
Suction Side ◽  
Solid Particles ◽  
Working Fluid ◽  
Average Particle ◽  
Pump Speed ◽  
Velocity Magnitude ◽  
Refractive Index Matching ◽  
Particle Velocities

The velocities of the slurry particles in the impeller of a centrifugal slurry pump were obtained utilizing Particle image velocimetry (PIV) technique in conjunction with refractive index matching. Tests were performed in an optically clear centrifugal slurry pump at speeds of 725 rpm and 1000 rpm using a slurry made up of sodium iodide solution as a working fluid and glass beads (500μm mean diameter) as solid particles at volumetric concentrations of 1%, 2%, and 3%. In the intra blade region of the impeller, the highest particle velocities were obtained in the suction side of the blade and in the blade trailing edge region as the blade sweeps through and velocity magnitude increases with the increase in the pump speed. But this magnitude was less than that of circumferential velocity of the blade tip. The average particle velocities were obtained and it was found that the average particle velocity decreases with increase in concentration. The fluctuating component of particle velocity, which is related to the fluctuation kinetic energy were obtained. With the increase in the particle volumetric concentration, fluctuation kinetic energy decreases and the maximum fluctuation kinetic energy typically occurs on the suction side of the blade. The slurry particles are pushed on the pressure side of the blade and slide on it which can result in frictional wear. These results are discussed in this paper.

scholarly journals Diffusiophoresis of a Colloidal Cylinder at Small Finite Péclet Numbers

2019 ◽  
Vol 3 (2) ◽  
pp. 44
Author(s):  
Chang ◽  
Keh
Keyword(s):  
Particle Velocity ◽  
Asymptotic Expansions ◽  
Concentration Gradient ◽  
Interfacial Layer ◽  
Fluid Velocity ◽  
Solute Concentration ◽  
Cylindrical Particle ◽  
Governing Equations ◽  
Nonelectrolyte Solution ◽  
Solute Convection

The diffusiophoretic migration of a circular cylindrical particle in a nonelectrolyte solution with a solute concentration gradient normal to its axis is analytically studied for a small but finite Péclet number . The interfacial layer of interaction between the solute molecules and the particle is taken to be thin, but the polarization of its mobile molecules is allowed. Using a method of matched asymptotic expansions, we solve the governing equations of conservation of the system and obtain an explicit formula for the diffusiophoretic velocity of the cylinder correct to the order . It is found that the perturbed solute concentration and fluid velocity distributions have the order , but the leading correction to the particle velocity has the higher order . The correction to the particle velocity to the order can be either positive or negative depending on the polarization parameter of the thin interfacial layer, establishing that the solute convection effect is complicated and can enhance or retard the diffusiophoretic motion. The particle velocity at can be about 17% smaller or 0.2% greater than that at . Under practical conditions, the solute convection effect on the diffusiophoretic velocity is much greater for a cylindrical particle than for a spherical particle, whose leading correction has the order .

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