Gonzalez, Diego

A pre-study of free burning arcs between carbon electrodes for potential use in gasification processes is presented. Free-burning arcs offer the potential to be used without additional gas feed or significant changes to gas flows in established gasification systems as well as with minimal cooling requirements for improved energy efficiency. Direct current (DC) arcs with currents up to 200 A and power levels up to 40 kW have been operated in molecular gas mixtures of H2, CO and CO2.

Double-pulse laser induced breakdown spectroscopy (LIBS) measurements in water with up to 600 bar hydrostatic pressure and 150 mJ energy of each pulse were done to select a setup which promote separated spectral lines in the observed plasma emission even at elevated pressures, where line broadening until loss of the most spectral information can occur. For this a compact spectrometer und a Czerny-Turner spectrometer, both fiber-based, has been applied to investigate the dependence of the emitted radiation on different parameters and hydrostatic pressure.

Double-pulse laser induced breakdown spectroscopy (LIBS) measurements in water with up to 600 bar and 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures, where line broadening until loss of the most spectral information can occur. Optical emission spectroscopy, using a Czerny-Turner spectrometer, has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic pressure.

In this work we present for the first time a unified model of a low-current short-length arc between copper electrodes. The model employs one-dimensional fluid description of the plasma in argon and copper vapour at atmospheric pressure and the heat transfer in the electrodes made of copper. The solution of the particle and energy conservation of electrons and heavy particles is coupled with the solution of the Poisson equation, from which the self-consistent electric field is obtained. The operation of the non-refractory cathode is based on thermo-field emission.