Master of Engineering Science
Electrical and Computer Engineering
Corona discharge is used in many practical applications. For designing and optimization of corona devices, the discharge phenomenon should be numerically simulated. Most often, the corona discharge model is simplified by neglecting the process dynamics and assuming a limited number of reactions and species. In the extreme case, monopolar corona models with just one species and no reactions are studied. However, there is a problem with determining boundary conditions for the space charge density. The simplest solution to this problem was suggested by Kaptzov, who hypothesized that the electric field on the electrode surface remains constant and equal to the value at the onset conditions, which is known from a semi-empirical Peek’s formula. Experimental data confirm good accuracy of this approach. However, it is impossible to experimentally measure the surface electric field at different voltage levels and compare it to Peek’s value. Our thesis will discuss different methods for simulating corona discharge in 1D wire-cylinder geometry in air at atmospheric pressure. The classical model based on Kaptzov’s hypothesis is compared with other approaches. The first model is still a single-species one, but it uses direct ionization criterion. Two other models consider a higher number of species and some number of reactions, so the ionization layer is included. The surface electric field can differ from Peek’s value by almost 43%. In addition, the results of numerical investigations of the EHD flow generated by dc corona discharge in the point-plane configuration in atmospheric air are presented in this thesis. A computational model of the discharge includes the ionization layer and three ionic species. The most important ionic reactions (ionization, attachment, recombination and detachment) are considered. The results of the corona simulations were used to predict the secondary EHD flow. All flow parameters (velocity components, pressure, streamlines) are determined. In addition to main flow vortex reported before, a local vortex near the discharge tip has also been discovered. COMSOL, a commercial finite element package, was used in simulations.
Mantach, Sara, "Simplified Numerical Models in Simulating Corona Discharge and EHD Flows" (2018). Electronic Thesis and Dissertation Repository. 5357.