Primena globalnih modela u analizi fizičkih i hemijskih procesa u niskotemperaturnim plazmama na atmosferskom pritisku

Abstract

The main goal of research in this dissertation is the studying of physical and chemical processes in atmospheric pressure low temperature plasmas, formed in the mixture of He or He/O2 with humid air, based on application of 0D global models. Electron energy distribution function in the two term approximation and rate coefficients for electron impact processes, necessary for solving the balance equations of global model, have been calculated by numerical solving of Boltzmann kinetic equation with program BOLSIG+, with cross section data taken from databases LXCat and Quantemol-DB. Using the model of electron swarm, the influence of cross section dataset on distribution function and transport coefficients has been studied. In the case of He/O2 RF micro-plasma jet with some percent of humid air, the influence of electron concentration on electron energy distribution function and plasma composition has been studied by global model. In the case of pulsed (ns) He plasma jet formed in mixture of plasma with humid air, the influence of water vapor concentration on the main production and destruction channels for OH radical has been analyzed and results have been compared with the results of fluid model in literature. Global model was expanded by including the calculation of electron concentration and temperature, and the term for gas flow. The model has been verified in the procedure of modeling the mass spectrum of ions, for He plasma jet which propagates in humid air, measured in the Laboratory of gaseous electronics, Institute of physics Belgrade. Chemical kinetics of active species, important for application in biomedicine and agriculture, has been studied in detail. The influence of water vapor on electron concentration, electron temperature and chemical kinetics of all included species has been analyzed.