Microparticle Dynamics in Electrostatic and Flow Fields PDF Download
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Author: Sheng Chen
Publisher:
ISBN: 9789811608445
Category :
Languages : en
Pages : 0
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Book Description
This thesis proposes new approaches for modelling contacting interactions and electrostatic interactions between microparticles in the framework of the discrete element method and presents a systematic investigation on the agglomeration, migration and deposition of microparticles in presence of electrostatic and flow fields. It reports an exponential-form scaling for the size distribution of early-stage agglomerates in homogeneous isotropic turbulence and formulate the agglomeration and deagglomeration rates. The evolution of spherical clouds of charged particles that migrate under the action of an external electrostatic field is then investigated. Scaling laws of cloud radius and particle number density are obtained by solving a continuum convection equation. Finally, it investigates the deposition of charged particles on a flat plane and fibers. A dimensionless adhesion parameter is constructed to predict the structure of deposits. The temporal evolution of the deposit structure, particle capture efficiency, and the pressure drop are displayed with varying values of Coulomb repulsion and adhesion magnitudes. .
Author: Sheng Chen
Publisher:
ISBN: 9789811608445
Category :
Languages : en
Pages : 0
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Book Description
This thesis proposes new approaches for modelling contacting interactions and electrostatic interactions between microparticles in the framework of the discrete element method and presents a systematic investigation on the agglomeration, migration and deposition of microparticles in presence of electrostatic and flow fields. It reports an exponential-form scaling for the size distribution of early-stage agglomerates in homogeneous isotropic turbulence and formulate the agglomeration and deagglomeration rates. The evolution of spherical clouds of charged particles that migrate under the action of an external electrostatic field is then investigated. Scaling laws of cloud radius and particle number density are obtained by solving a continuum convection equation. Finally, it investigates the deposition of charged particles on a flat plane and fibers. A dimensionless adhesion parameter is constructed to predict the structure of deposits. The temporal evolution of the deposit structure, particle capture efficiency, and the pressure drop are displayed with varying values of Coulomb repulsion and adhesion magnitudes. .
Author: 陈晟
Publisher:
ISBN: 9787302619543
Category : Electrostatics
Languages : en
Pages : 0
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Book Description
Author: Sheng Chen
Publisher: Springer Nature
ISBN: 9811608431
Category : Technology & Engineering
Languages : en
Pages : 153
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Book Description
This thesis proposes new approaches for modelling contacting interactions and electrostatic interactions between microparticles in the framework of the discrete element method and presents a systematic investigation on the agglomeration, migration and deposition of microparticles in presence of electrostatic and flow fields. It reports an exponential-form scaling for the size distribution of early-stage agglomerates in homogeneous isotropic turbulence and formulate the agglomeration and deagglomeration rates. The evolution of spherical clouds of charged particles that migrate under the action of an external electrostatic field is then investigated. Scaling laws of cloud radius and particle number density are obtained by solving a continuum convection equation. Finally, it investigates the deposition of charged particles on a flat plane and fibers. A dimensionless adhesion parameter is constructed to predict the structure of deposits. The temporal evolution of the deposit structure, particle capture efficiency, and the pressure drop are displayed with varying values of Coulomb repulsion and adhesion magnitudes.
Author: Jeffery S. Marshall
Publisher: Cambridge University Press
ISBN: 1107032075
Category : Mathematics
Languages : en
Pages : 361
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Book Description
This is targeted at professionals and graduate students working in disciplines where flow of adhesive particles plays a significant role.
Author: Aa.vv.
Publisher: Gruppo Italiano Frattura
ISBN: 8895940407
Category : Reference
Languages : en
Pages : 366
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Book Description
Annals of the Italian Group of Fracture journal "Frattura ed Integrità Strutturale" (issues 7 - 10, 2009)
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 324
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Book Description
Author: Francesco Lattarulo
Publisher: John Wiley & Sons
ISBN: 1118821068
Category : Technology & Engineering
Languages : en
Pages : 213
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Book Description
Presents all-new laboratory-tested theory for calculating more accurate ionized electric fields to aid in designing high-voltage devices and its components Understanding and accurately calculating corona originated electric fields are important issues for scientists who are involved in electromagnetic and electrostatic studies. High-voltage dc lines and equipment, in particular, can generate ion flows that can give rise to environmental inconveniences. Filamentary Ion Flow: Theory and Experiments provides interdisciplinary theoretical arguments to attain a final model for computational electrostatics in the presence of flowing space charge. Based on years of extensive lab tests pertaining to the physical performance of unipolar corona ion flows, the book covers the enlarging of conventional electrostatic applications, which allows for some emerging and uncharted interests to be explored. Filamentary Ion Flow: Examines the theoretical discussions for creating a model of computational electrostatics involved with flowing space charges Presents new theory and experimental data based on extensive testing Offers potential design applications utilizing the theory Helps scientists who are involved in electromagnetic and electrostatic studies understand and accurately calculate corona originated ion flow fields Filamentary Ion Flow: Theory and Experiments is ideal for electrical engineers and research scientists interested in high-voltage technology, computational electrostatics, and electromagnetic theory.
Author:
Publisher:
ISBN:
Category : Computers
Languages : en
Pages : 646
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Book Description
Author: Hsin-Fu Huang
Publisher:
ISBN:
Category :
Languages : en
Pages : 288
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Book Description
The negative electrorheological responses of two dimensional Couette and Poiseuille flows with internal micro-particle electrorotation are modeled and analyzed via a set of "fully continuum mechanical modeling field equations" formulated in this thesis. By combining the theories of particle electromechanics and continuum anti-symmetric/couple stresses, general governing equations are presented to describe the physical aspects of mass conservation, linear momentum balance, angular momentum balance, and electro-quasi-static field of the negative electrorheological fluid flow. A "rotating coffee cup model" is also developed for the first time to derive the retarding polarization relaxation equation with its accompanying equilibrium retarding polarization in order to characterize the non-equilibrium motion effects of the continuum spin velocity, co, continuum linear velocity, v, and micro-particle rotation speed, n, on the polarization responses as well as the electrical body torque inputs in the negative electrorheological flow field. Using the general assumptions of steady, incompressible, fully developed, and two dimensional flows, we reduce and simplify the full general governing equations in the zero spin viscosity and the finite spin viscosity small spin velocity limits for both Couette and Poiseuille flow geometries. In the zero spin viscosity limit, expressions for the spin velocity and effective viscosity of Couette flow as well as the spin velocity, linear velocity, and two dimensional volume flow rate of Poiseuille flow are derived in terms of the applied direct current electric field strength, shear rate (for Couette flow), driving pressure gradient (for Poiseuille flow), and spatial coordinate by solving the simplified continuum linear and angular momentum equations with the linear flow velocity being subjected to the no-slip boundary condition. As for the finite spin viscosity small spin velocity limit, analytical solutions to the spin velocity, linear velocity, and effective viscosity of Couette flow as well as solutions to the spin velocity, linear velocity, and two dimensional volume flow rate of Poiseuille flow are obtained and expressed in terms of the applied direct current electric field strength, boundary condition selection parameter (p), spin viscosity, and driving shear rate (for Couette flow) or pressure gradient (for Poiseuille flow) by solving a set of differential equations coupling the linear and angular momentum balances of the negative electrorheological fluid flow subjected to the no-slip and co=0.5/Vxv (with 0, 1) boundary conditions. After obtaining the solutions in the respective zero spin viscosity and finite spin viscosity small spin velocity limits, series of parametric studies are then performed on these solutions via varying the pertinent physical parameters involved in several parametric regimes of interest so as to illustrate the negative electrorheological behavior and fluid flow response due to internal micro-particle electrorotation. Modeling results in the two limits generally show that with a direct current electric field applied perpendicularly to the flow direction, the spin velocity is increased and the effective viscosity is decreased as compared to the zero electric field values of the electrorheological fluid flow in Couette geometries at a given driving shear rate. It is also found that with a constant driving pressure gradient, the internal micro-particle electrorotation induces increased continuum fluid spin velocity, linear flow velocity, and two-dimensional volume flow rate on the macroscopic level in Poiseuille flow geometries when a direct current electric field perpendicular to the direction of flow is applied. Results of the Couette effective viscosity and Poiseuille volume flow rate obtained from our present continuum mechanical formulation are further compared to the experimental measurements as well as modeling results from single particle dynamics based two-phase volume averaged effective medium analysis found in current literature. With the "rotating coffee cup" fluid polarization model, the present zero spin viscosity continuum solutions to the effective viscosity and volume flow rate agree with the theoretical solutions obtained from single particle dynamics analysis. The zero spin viscosity solutions to the Couette effective viscosity also fall closer to the experimental measurements reported in current literature for low to moderate direct current electric field strengths. Moreover, the present continuum mechanical formulation in the finite spin viscosity small spin velocity limit is more capable of accurately capturing the negative electrorheological flow responses in the low shear rate and low driving pressure gradient flow regimes characterized by the respective Couette effective viscosity and Poiseuille volume flow rate. These finite spin viscosity small spin velocity results agree better with previous experimental measurements reported in the literature and bring the theoretical modeling of the negative electrorheological flow phenomenon due to internal micro-particle electrorotation closer to physical reality-both of which were generally not possible in previous literature. This important improvement in modeling the negative electrorheological response considered in this thesis is due to our proposed "rotating coffee cup model," which is likely the first model to treat the continuum spin velocity and the micro-particle rotation speed as separate physical variables. Using the finite spin viscosity small spin velocity analysis, we also derive for the first time a characteristic length scale determined by the balances between the electrical body torque input and the angular momentum conversion between the linear and spin velocity fields, which can be used to explain why the present continuum zero spin viscosity solutions are very much similar to those obtained from single particle dynamics based two-phase volume averaged effective medium analysis found in current literature. Future work includes a more advanced modeling of the polarization relaxation processes in the negative electrorheological fluid flow, the full non-linear analysis of finite spin viscosity effects on the angular momentum balances within the electrorheological flow field without the restriction of the small spin velocity limit, and the search of possible applications of our proposed continuum mechanical modeling field equations theory in the research areas of micro/nano-fluidics, biofluid dynamics, and engineering torque-shear rate control systems.
Author: John Farrell Hughes
Publisher: Taylor & Francis Group
ISBN:
Category : Science
Languages : en
Pages : 198
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Book Description
A fundamental look at how individual solid particles may be electrically charged and manipulated in such a way as to be of practical use. Powder coating, precipitation and electrocopying are the three most familiar applications of charged particles. In addition, this books highlights less well-known applications, including those related to health care.Provides wide coverage of applications, including electrostatic control of airborne allergens. -- Mathematics is kept to a minimum, making the book accessible to newcomers as well as specialists in the field. -- Includes discussion of future trends in this emerging field.
