Numerical Simulation of Particle Trajectory in Electrostatic Precipitator

2014 ◽  
Vol 568-570 ◽  
pp. 1743-1748
Author(s):  
Deng Feng Chen ◽  
Xiao Dong Yang ◽  
Hai Yan Xiao
Keyword(s):  
Electric Field ◽  
Particle Motion ◽  
Gas Flow ◽  
Particle Trajectory ◽  
Electrostatic Precipitator ◽  
Stokes Equations ◽  
Numerical Models ◽  
Discrete Phase Model ◽  
Electrostatic Forces ◽  
Complex Flow

The performance of Electrostatic Precipitator (ESP) is significantly affected by complex flow distribution. Recent years, many numerical models have been developed to model the particle motion in the electrostatic precipitators. The computational fluid dynamics (CFD) code FLUENT is used in description of the turbulent gas flow and the particle motion under electrostatic forces. The gas flow are carried out by solving the Reynolds-averaged Navier-Stokes equations and turbulence is modeled by the k-ε turbulence model. The effect of electric field is described by a series equations, such as the electric field and charge transport equations, the charged particle equation, the charge conservation equation, the mass and momentum equations of gas, the mass and momentum equations of particle and so on. The particle phase is simulated by using Discrete Phase Model (DPM). The simulations showed that the particle trajectory inside the ESP is influenced by both the aerodynamic and electrostatic forces. The simulated results have been validated by the established data.

scholarly journals Numerical Modeling of Tsunami Waves Interaction with Porous and Impermeable Vertical Barriers

2012 ◽  
Vol 2012 ◽  
pp. 1-27 ◽  
Author(s):  
Manuel del Jesus ◽  
Javier L. Lara ◽  
Inigo J. Losada
Keyword(s):  
Stokes Equations ◽  
Tsunami Wave ◽  
Numerical Models ◽  
Wave Interaction ◽  
Wave Pattern ◽  
Navier Stokes ◽  
Economic Losses ◽  
Wave Flow ◽  
Complex Flow ◽  
Tsunami Waves

Tsunami wave interaction with coastal regions is responsible for very important human and economic losses. In order to properly design coastal defenses against these natural catastrophes, new numerical models need to be developed that complement existing laboratory measurements and field data. The use of numerical models based on the Navier-Stokes equations appears as a reasonable approach due to their ability to evaluate complex flow patterns around coastal structures without the inherent limitations of the classical depth-averaged models. In the present study, a Navier-Stokes-based model, IH-3VOF, is applied to study the interaction of tsunami waves with porous and impermeable structures. IH-3VOF is able to simulate wave flow within the porous structures by means of the volume-averaged Reynolds-averaged Navier-Stokes (VARANS) equations. The equations solved by the model and their numerical implementation are presented here. A numerical analysis of the interaction of a tsunami wave with both an impermeable and porous vertical breakwater is carried out. The wave-induced three-dimensional wave pattern is analysed from the simulations. The role paid by the porous media is also investigated. Finally, flow around the breakwater is analyzed identifying different flow behaviors in the vicinity of the breakwater and in the far field of the structure.

Leakage Estimate in Nonuniformly Compressed Packing Rings

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Ali Salah Omar Aweimer ◽  
Abdel-Hakim Bouzid ◽  
Zijian Zhao
Keyword(s):  
Analytical Model ◽  
Gas Flow ◽  
Stokes Equations ◽  
Numerical Models ◽  
Fluid Dynamic ◽  
Experimental Studies ◽  
Axial Distance ◽  
Radial Compression ◽  
Packing Materials ◽  
Packing Ring

Abstract Characterizing the permeation performance of nanoporous material is an initial step toward predicting microflows and achieving acceptable designs in sealing and filtration applications. This study deals with analytical, numerical, and experimental studies of gaseous leaks through soft packing materials subjected to nonuniform axial compression in valve stuffing boxes. A new analytical model that accurately predicts gaseous leak rates through nanoporous packing materials assumed made of capillaries having an exponentially varying section. Based on Navier–Stokes equations with the first-order velocity slip condition for tapered cylinder capillaries, the analytical model is used to estimate gas flow through soft packing materials. In addition, computational fluid dynamic modeling using cfx software is used to test its capacity to estimate the permeation of compression packing ring materials assuming the fluid flow to follow Darcy's law. Helium gas is used as a reference gas in the experiments to characterize the porosity parameters. The analytical and cfx numerical leak predictions are compared to leak rates measured experimentally using different gas types (helium, nitrogen, air, and argon) at different pressures and gland stresses. The analytical and numerical models account for the porosity change with the stem axial distance because the packing ring set is subjected to an exponentially varying radial compression. The predictions from analytical model are in close agreement with the cfx model and in better agreement with experimental measurements.

Prediction of Turbo Air Classifier Cut Size Based on Particle Trajectory

2016 ◽  
Author(s):  
Yuan Yu ◽  
Mehdi Saadat ◽  
Alexandrina Untaroiu ◽  
Benjamin R. Thomas ◽  
Houston G. Wood
Keyword(s):  
Numerical Simulation ◽  
Gas Flow ◽  
Particle Trajectory ◽  
Stokes Equations ◽  
Particle Density ◽  
Reference Method ◽  
Classification Performance ◽  
Theoretical Formula ◽  
Important Indicator ◽  
Air Classifier

As a mainstream dynamic dry classifer, the turbo air classifier is widely used in powder preparation industries for its adjustable cut size, controllable product granularity and high classification performance. As an important indicator for evaluating the classification performance of a turbo air classifier, cut size is often predicted in advance to evaluate classification effect so that the operation parameters can be adjusted suitably according to the production requirement. There are two common ways to obtain cut size of turbo air classifiers. One is based on a theoretical formula; another is based on an experimentally derived formula. There are a few problems with the aforementioned ways of predicting cut size. The theoretical analysis often has some large deviations from the actual values. Analysis based on empirical formula can obtain an accurate predicted cut size at the cost of a large number of training samples. In this paper, a new strategy is introduced to determine the cut size based on numerical simulation of gas-solid two-phase flow in the turbo air classifier using ANSYS® CFX, Release 15.0. The three-dimensional Reynolds-averaged Navier-Stokes equations along with the k-ε turbulence model are adopted to describe the gas flow, and the Lagrangian particle tracking technique is used to calculate the particle trajectory. According to its definition, cut size can be obtained by means of analyzing the particle trajectory. The effects of rotor cage rotational speed and particle density on cut size are also obtained based on analysis of the change of cut size. The simulation results are validated against the experimental data. Numerical simulation provides a new way to obtain the cut size of a turbo air classifier and serves as a method to regulate the operating parameters for classification. It also provides a reference method to study the cut size of various types of classifier.

Study on Drug Powder Acceleration in a Micro Shock Tube

2015 ◽  
Author(s):  
Guang Zhang ◽  
Heuy Dong Kim ◽  
Yingzi Jin ◽  
Toshiaki Setoguchi
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Shock Tube ◽  
Gas Flow ◽  
Stokes Equations ◽  
Supersonic Nozzle ◽  
Particle Diameter ◽  
Shock Wave Propagation ◽  
Finite Volume Scheme ◽  
Discrete Phase Model

Recently, needle-free drug delivery systems have been widely used for delivering drug particles into human body without any external needles in medical fields. Drug powders should be accelerated to obtain enough momentum to be delivered into the suitable layer of the skin. This is achieved by accelerating drug particles in a Contoured Shock Tube (CST) which consists of a micro shock tube and an expanded supersonic nozzle. Shock wave happens in micro shock tube, and supersonic flow with particles is induced by the shock wave and accelerated in the expanded nozzle. Even though micro shock tubes have been studied for a long time, detailed experimental data for shock waves and particle-gas flows are sparse to date and it is very important to investigate the complicated particle-gas flow fields for practical applications. In the present study, Particle Tracking Velocimetry (PTV) was used to measure the average velocity of the gas-particle flow behind the propagating shock wave. Unsteady flow properties and shock wave propagation were analyzed by this instantaneous particle velocity fields. Numerical simulation was performed with unsteady compressible Naver-stokes equations which were solved by using a fully implicit finite volume scheme. Discrete Phase Model (DPM) has been used for simulating particle-gas two-phase flows. Different particle diameter and density were performed in present numerical studies. Unsteady particle-gas flow characteristics and shock wave propagation have been studied and analyzed in details in present micro shock tube model.

Simulation of TiO 2 particle trajectory in AC electric field

2015 ◽  
Vol 108 ◽  
pp. 183-191 ◽  
Author(s):  
Reza Riahifar ◽  
Babak Raissi ◽  
Cyrus Zamani ◽  
Ehsan Marzbanrad
Keyword(s):  
Electric Field ◽  
Particle Trajectory ◽  
Ac Electric Field

scholarly journals Rock Particle Motion Information Detection Based on Video Instance Segmentation

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4108
Author(s):  
Man Chen ◽  
Maojun Li ◽  
Yiwei Li ◽  
Wukun Yi
Keyword(s):  
Loss Function ◽  
Particle Motion ◽  
Numerical Models ◽  
Major Axis ◽  
Angular Distance ◽  
Motion Information ◽  
Vibration Load ◽  
Rock Particle ◽  
Information Detection ◽  
Instance Segmentation

The detection of rock particle motion information is the basis for revealing particle motion laws and quantitative analysis. Such a task is crucial in guiding engineering construction, preventing geological disasters, and verifying numerical models of particles. We propose a machine vision method based on video instance segmentation (VIS) to address the motion information detection problem in rock particles under a vibration load. First, we designed a classification loss function based on Arcface loss to improve the Mask R-CNN. This loss function introduces an angular distance based on SoftMax loss that distinguishes the objects and backgrounds with higher similarity. Second, this method combines the abovementioned Mask R-CNN and Deep Simple Online and Real-time Tracking (Deep SORT) to perform rock particle detection, segmentation, and tracking. Third, we utilized the equivalent ellipse characterization method for segmented particles, integrating with the proportional calibration algorithm to test the translation and detecting the rotation by calculating the change in the angle of the ellipse’s major axis. The experimental results show that the improved Mask R-CNN obtains an accuracy of 93.36% on a self-created dataset and also has some advantages on public datasets. Combining the improved Mask R-CNN and Deep SORT could fulfill the VIS with a low ID switching rate while successfully detecting movement information. The average detection errors of translation and rotation are 5.10% and 14.49%, respectively. This study provides an intelligent scheme for detecting movement information of rock particles.

scholarly journals Development of Calculation Model for Metallic Particle Motion Considering Discharge Phenomenon under High Voltage Electric Field in SF6 Gas

2006 ◽  
Vol 126 (1) ◽  
pp. 73-79
Author(s):  
Toshiaki Rokunohe ◽  
Tomohiro Moriyama ◽  
Yoshitaka Yagihashi ◽  
Makoto Koizumi ◽  
Fumihiro Endo
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Particle Motion ◽  
Calculation Model ◽  
Metallic Particle

Numerical Investigation of the Coulter Principle in a Microfluidic Device

2013 ◽  
Author(s):  
Muheng Zhang ◽  
Yongsheng Lian
Keyword(s):  
Electric Field ◽  
Stokes Equations ◽  
Equations Of Motion ◽  
Navier Stokes ◽  
Working Mechanism ◽  
Navier Stokes Equations ◽  
Sheath Flow ◽  
Coulter Counters ◽  
Pass Through ◽  
Cell Motion

Coulter counters are analytical microfluidic instrument used to measure the size and concentration of biological cells or colloid particles suspended in electrolyte. The underlying working mechanism of Coulter counters is the Coulter principle which relies on the fact that when low-conductive cells pass through an electric field these cells cause disturbances in the measurement (current or voltage). Useful information about these cells can be obtained by analyzing these disturbances if an accurate correlation between the measured disturbances and cell characteristics. In this paper we use computational fluid dynamics method to investigate this correlation. The flow field is described by solving the Navier-Stokes equations, the electric field is represented by a Laplace’s equation in which the conductivity is calculated from the Navier-Stokes equations, and the cell motion is calculated by solving the equations of motion. The accuracy of the code is validated by comparing with analytical solutions. The study is based on a coplanar Coulter counter with three inlets that consist of two sheath flow inlet and one conductive flow inlet. The effects of diffusivity, cell size, sheath flow rate, and cell geometry are discussed in details. The impacts of electrode size, gap between electrodes and electrode location on the measured distribution are also studied.

Gas and solids motion around deformed and interacting bubbles in fluidized beds

1972 ◽  
Vol 51 (1) ◽  
pp. 187-205 ◽  
Author(s):  
R. Clift ◽  
J. R. Grace ◽  
L. Cheung ◽  
T. H. Do
Keyword(s):  
Particle Motion ◽  
Fluidized Beds ◽  
Gas Flow ◽  
Theoretical Models ◽  
Flow Patterns

Previous analyses of gas and particle motion around bubbles in fluidized beds have concentrated on idealized isolated bubbles. In this paper three non-idealities are considered using the theoretical models of Davidson and Murray. Gas flow patterns are derived for indented and elongated bubbles and for pairs of interacting bubbles. Cloud boundaries are predicted for these situations and some effects on gas-solid contacting are discussed.

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