Kazimierz Adamiak

Finite element force calculation: comparison of methods for electric machines

Results of torque and thrust calculation using the finite-element method are presented. The calculations make use of the Maxwell stress tensor, the virtual work principle, and the Lorentz formula. Calculations for two types of machines are considered: the switched reluctance motor and the linear induction motor. Computational results are validated by comparison with the shortcomings and the advantages of the different methods. >

Simulation of corona in wire-duct electrostatic precipitator by means of the boundary element method

An approach for modeling the space charge density and the electric field distribution in electrostatic precipitators is presented. Two numerical techniques are used iteratively until a self-consistent solution is obtained: the boundary element method, for evaluation of the electric potential, and the characteristic method, determining the charge distribution. This hybrid approach is applied to simulate the electrical conditions in a wide-duct electrostatic precipitator and obtained results are compared with the experimental data.<<ETX>>

Numerical Simulation of the Electrohydrodynamic Flow in a Single Wire-Plate Electrostatic Precipitator

In this paper, the electrohydrodynamic (EHD) flow in a single wire-plate electrostatic precipitator has been analyzed numerically by employing a hybrid Finite-Element Method-Method of Characteristics numerical algorithm and the commercial computational fluid dynamic software FLUENT6.2. Parameters defining both the electric and the flow fields were predicted. The interaction between the electric and the flow fields has been discussed by adopting the proposed two-way coupling algorithm. With the help of the dimensionless analysis, an entire flow regime map has been developed for different Reynolds (Re) and EHD numbers. It was found that, at very low Re (15) and high EHD (2000) (based on the corona wire) numbers, the EHD flow dominates in the channel; as Re increases, the significance of the EHD wakes gradually decreases; at a higher Re (50) or a lower EHD (500) numbers, the EHD flow becomes the near-corona-wire phenomena, and the main flow dominates the channel. The possible influence of the EHD flow on the particle-collection efficiency was also discussed.

Adaptive approach to finite element modelling of corona fields

A methodology is proposed for simulating the corona field under a high-voltage DC (HVDC) transmission line. In the finite element modeling of corona fields, the area close to the corona electrode needs the finest discretization due to a significant difference in size and curvature of electrodes. User-defined discretization may yield insufficient accuracy. In the approach presented here, the domain is discretized adaptively according to an algorithm based on information about the solution error. There are two advantages of such an approach: mesh generation is completely automatic, and the resultant mesh has the optimum density for the assumed accuracy. This adaptive algorithm has been demonstrated for several HVDC transmission line configurations.<<ETX>>

Trichel pulse characteristics—negative corona discharge in air

In this paper a three-species two-dimensional model is used for the simulation of the Trichel pulse regime of corona discharge in air for a point-plane configuration. Effects of different parameters of the model on Trichel pulse characteristics (Trichel pulse period and the average corona current) are studied. The parameters of interest are external resistance of the circuit, secondary electron emission coefficient and negative and positive ion mobilities. Moreover, the numerical simulation was performed for the configuration used in the experimental analysis reported in the literature and the results proved to be very compatible.

Numerical modelling of tribo-charge powder coating systems

Abstract A numerical algorithm for simulating the electric field distribution and particle trajectories in tribo-charge powder coating systems is presented. It combines the finite element method for the electric field analysis and the numerical integration of the equation for the particle trajectories. The particle-in-cell technique is used to couple both methods, which are applied iteratively until a self-consistent solution is obtained.

Numerical Simulation of Trichel Pulses in a Negative Corona Discharge in Air

In this paper, a new 2-D model is presented for numerical simulation of Trichel pulses in a point-plane configuration. Both radial and axial components of the electric field are considered and it is assumed that three ionic species exist in the air gap: electrons, and positive and negative oxygen ions. The Poisson equation is solved for electric field calculations and three continuity equations for modeling the transport of charge densities in the air gap. The finite element method (FEM) is used for solving the Poisson equation and a combined Flux Corrected Transport-FEM is used for the charge transport equations. Trichel pulses for different applied voltages are shown and the characteristics of these pulses at different voltages are compared with experimental results reported in the literature. The time variation of the electric field on the corona electrode at different stages of one Trichel pulse is also presented. Moreover, the distributions of electron, positive ion and negative ion densities at different stages of the Trichel pulse are discussed.

Numerical Simulation of the 2-D Gas Flow Modified by the Action of Charged Fine Particles in a Single-Wire ESP

A numerical model for simulating precipitation of submicrometer particles in a singlewire electrostatic precipitator is discussed in this paper. It includes all important phenomena affecting the process: electric field, space charge density, gas flow, including the secondary electrohydrodynamic flow caused by the corona discharge and charged particles, and particle transport. A simplified corona model assumes just one ionic species and neglects the ionization zone. The fully coupled model for the secondary EHD flow, considering the ion convection, has been implemented. The dust particles are charged by ionic bombardment and diffusion. The gas flow pattern is significantly modified by the secondary EHD flow, which depends on the particle concentration. As for fine particles the drift velocity is small and particles practically follow the gas streamlines, the particle concentration has a very strong effect on the precipitation efficiency.

Particle charging by unipolar ionic bombardment in an AC electric field

A numerical technique for simulating electrical conditions in a charging device for high resistivity powders in an electrostatic precipitator is presented. The device consists of two independent sets of electrodes; the first one, supplied with high DC voltage, produces the ionic discharge, and the second, connected to an AC voltage source, prevents precipitation of charged particles. The algorithm presented predicts the electric field and space charge density in the charging zone and then simulates trajectories of particles and the rate of charging. The results of simulation in a number of cases show the influence of different parameters on the work of the device. >

FEM–FCT-Based Dynamic Simulation of Corona Discharge in Point–Plane Configuration

In this paper, a numerical algorithm for the simulation of the dynamic corona discharge in air is proposed assuming single-species charge carriers. The simulation results show the behavior of corona current and space-charge density under two waveforms of the applied voltage: step and pulse. The electric field is calculated by means of the finite-element method, and the flux-corrected transport technique is utilized for the space-charge-density calculations.