Effect of the particle diameter and corona electrode geometry on the particle migration velocity in electrostatic precipitators

2001 ◽  
Vol 51-52 ◽  
pp. 245-251 ◽  
Author(s):  
Maria Jędrusik ◽  
Juliusz B. Gajewski ◽  
Arkadiusz J. Świerczok
Keyword(s):  
Particle Diameter ◽  
Migration Velocity ◽  
Particle Migration ◽  
Electrode Geometry ◽  
Electrostatic Precipitators ◽  
Corona Electrode

scholarly journals Formation of sediment patterns in channel flow: minimal unstable systems and their temporal evolution

2017 ◽  
Vol 818 ◽  
pp. 716-743 ◽  
Author(s):  
Aman G. Kidanemariam ◽  
Markus Uhlmann
Keyword(s):  
Pattern Formation ◽  
Channel Flow ◽  
Power Law ◽  
Particle Diameter ◽  
Migration Velocity ◽  
Box Dimension ◽  
Computational Domain ◽  
Clear Fluid ◽  
Interface Shear ◽  
The Mean

The phenomenon of sediment pattern formation in a channel flow is numerically investigated by performing simulations which resolve all the relevant length and time scales of the problem. The numerical approach employed and the flow configuration considered is identical to our previous study (Kidanemariam & UhlmannJ. Fluid Mech., vol. 750, 2014, R2), the only difference being the length of the computational domain. The latter was systematically varied in order to investigate its influence on the initiation and evolution aspects. By successively reducing the streamwise length, the minimum box dimension which accommodates an unstable sediment bed is revealed, thus determining the lower threshold of the unstable modes. For the considered parameter point, the cutoff length for pattern formation lies in the range 75–100 times the particle diameter (3–4 times the clear fluid height). We also simulate the flow in a very long streamwise box with a size of 48 times the clear fluid height (featuring well over one million particles), accommodating approximately 11 initial ripple units with a wavelength in the range of 100–110 particle diameters. The evolution of the amplitude of the patterns exhibits two regimes of growth: an initial exponential regime, with a growth rate independent of the chosen domain size, and a subsequent nonlinear regime which is strongly constrained by the domain length. In the small domain cases, after the initial exponential regime, the ripples evolve steadily, maintaining their shape and migration velocity, at a mean wavelength equal to the length of the domain. The asymmetric ripple shape is characterized by a spectrum which exhibits a power-law decay over the first few dominant non-dispersive modes propagating at the mean dune migration velocity. The rate of particle transport and the mean interface shear stress exhibited an increase with increasing ripple dimensions. Nevertheless, the relationship between the two was observed to be approximately described by the empirical power-law formula for sediment transport by Wong & Parker (J. Hydraul. Engng, vol. 132, 2006, pp. 1159–1168).

A numerical study of particle migration in porous media during produced water reinjection

2021 ◽  
pp. 1-34
Author(s):  
Tian Xia ◽  
Qihong Feng ◽  
Sen Wang ◽  
Qinglin Shu ◽  
Yigen Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Porous Media ◽  
Oil Recovery ◽  
Produced Water ◽  
Numerical Study ◽  
Particle Diameter ◽  
Particle Migration ◽  
Critical Ratio ◽  
Clear Understanding ◽  
The Impact

Abstract The clogging phenomenon often occurs during the reinjection of produced water due to the suspended particles, which will deteriorate the development efficiency. Many experimental and analytical methods have been introduced to solve this problem; however, few numerical approaches have been proposed to investigate the particle migration in the produced water reinjection process. Moreover, it is hard to obtain a clear understanding directly from the particle scale when the injected particles have different sizes. This paper employs a coupled lattice Boltzmann method and discrete element method (LBM-DEM) to study the aforementioned process. The method was validated by reproducing the Drafting-Kissing-Tumbling (DKT) process. Simulations of migration of injected particles with different sizes through porous media were conducted and three clogging scenarios had been identified. We investigated the impact of injected particle size distribution and porous media on particle migration and concluded the results in the polydisperse aspect. From the simulation, we can conclude that mix clogging is the scenario we should try to avoid. Besides, both critical ratio of particle diameter of porous media to median particle diameter of injected particles (D/d50) and critical standard deviation value exist. The particle size range should be as small as possible in economical limits and the D/d50 value should be larger than the critical value. Our results can provide a good guide for the produced water pretreatment, which can improve oil recovery.

Field Controlled Charge and Heat Transfer Involving Macroscopic Charged Particles in Liquids

1975 ◽  
Vol 97 (3) ◽  
pp. 429-434 ◽  
Author(s):  
P. W. Dietz ◽  
J. R. Melcher
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Charged Particles ◽  
Particle Diameter ◽  
Particle Migration ◽  
Electrically Conducting ◽  
Fluid Convection ◽  
Experimental Values ◽  
Insulating Liquid ◽  
Parallel Electrode

When an electric field is applied to a system of electrically conducting particles in an insulating liquid, the rates of charge and heat transfer are augmented. Charged during collisions in the field, the particles execute field-induced excursions between the electrodes interrupted by collisions with other particles. Thus a combination of particle migration and particle-induced fluid convection results in the increase in heat transfer. Experimental values for the Nusselt number are obtained for heat transfer across the parallel electrode configuration. The model developed using these results consists of a well-mixed central region with thermal boundary layers about one particle diameter thick near each electrode.

Computation of local permeability in granular soils using spatial time domain reflectometer

2022 ◽  
Vol 12 (1) ◽  
pp. 1-26
Author(s):  
V. S. R. Annapareddy ◽  
T. Bore ◽  
M. Bajodek ◽  
A. Scheuermann
Keyword(s):  
Time Domain ◽  
Particle Diameter ◽  
Time Domain Reflectometry ◽  
Particle Migration ◽  
Granular Soils ◽  
Practical Applications ◽  
Effective Particle ◽  
Local Permeability ◽  
Order Of Magnitude ◽  
Time Domain Reflectometer

This letter proposes semi-analytical methods to obtain the local permeability for granular soils based on indirect measurements of the local porosity profile in a large coaxial cell permeameter using spatial time domain reflectometry. The porosity profile is used to obtain the local permeability using the modified Kozeny-Carman and Katz-Thompson equations, which incorporated an effective particle diameter that accounted for particle migration within the permeameter. The profiles of the local permeability obtained from the proposed methods are compared with experimentally obtained permeability distributions using pressure measurements and flow rate. The permeabilities obtained with the proposed methods are comparable with the experimentally obtained permeabilities and are within one order of magnitude deviation, which is an acceptable range for practical applications.

Analysis of the Adhered Particle Secondary Migration on the Slider Air Bearing Surface

2016 ◽  
Author(s):  
Sen Liu ◽  
Sheng-Nan Shen ◽  
Li Hui ◽  
Fu-Hao Cui
Keyword(s):  
Particle Diameter ◽  
Particle Migration ◽  
Air Bearings ◽  
Particle Movement ◽  
Secondary Migration ◽  
Flow Shear ◽  
Slider Surface ◽  
Slider Air Bearing ◽  
Stationary Action ◽  
And Migration

An entrapped particle on the slider air bearings damages the surface of the slider or the disk. The study of particle movement on and the particle adhesion mechanism onto the slider surface is critical to reduce entrapped particle-induced damage. In this paper, we extend the previous work proposing a dynamical model of the adhesive particle redistribution and migration on the slider surface. The model predicts whether the adhered particle will remain stationary action of the aerodynamic forces. Further, particle behaviors after detachment are analyzed considering the effects of flow shear rate, particle diameter and properties. There are four particle movement styles on the slider surface. Finally, the particle migration trajectory and velocity with time on the slider surface are presented.

The effects of corona electrode geometry on the operational characteristics of an ESP

1981 ◽  
Vol 6 (1-6) ◽  
pp. 153-159
Author(s):  
George Rinard ◽  
Donald Rugg ◽  
Whitney Patten ◽  
Leslie Sparks
Keyword(s):  
Electrode Geometry ◽  
Operational Characteristics ◽  
Corona Electrode

Shear-Induced Size Segregation Phenomena in Bidisperse Suspensions

1994 ◽  
Vol 47 (6S) ◽  
pp. S236-S239 ◽  
Author(s):  
Gokul P. Krishnan ◽  
David T. Leighton
Keyword(s):  
Reynolds Number ◽  
Parallel Plate ◽  
Migration Velocity ◽  
Particle Migration ◽  
Size Segregation ◽  
Concentrated Suspension ◽  
Colloidal Spheres ◽  
Tracer Particles ◽  
Flow Geometry ◽  
Wide Gap

The behavior of tracer particles in a concentrated suspension of non-colloidal spheres sheared in a parallel plate viscometer at low Reynolds number was investigated. The tracer particles were shown to migrate radially, with the tracer particles larger than those making up the suspension migrating radially outward. The migration velocity of the large tracer particles was measured, and found to be consistent with a shear-induced migration scaling (Leighton and Acrivos, 1987b), however the direction of the migration was the reverse of that suggested by the experiments of Abbot, et al. (1991) in a wide gap Couette device. The particle migration and segregation described here are interpreted in terms of the curvature of the flow geometry.

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