Katashi Osaki

Treatment of CO2 gas by high-energy type plasma

Abstract As one of the applications of high-energy type plasma to environmental problems, the treatment of carbon dioxide gas was studied, and the fundamental experiment was carried out by using a gas tunnel type plasma jet. In this paper, the results about the electrical characteristics of plasma torch and the thermal efficiency are shown. The thermal efficiency of the plasma torch was increased as the mixing ratio of CO 2 gas into the working gas was increased.

Application feasibility of high-performance-type plasma jet device to various material processes

Abstract A newly designed high-performance-type plasma jet device for processing has been developed. This device can generate a high temperature and clean plasma jet and inject the process material into the center of the arc column. In order to demonstrate the application feasibility of this device to thermal processing, the effects of nozzle diameter and material loading on the characteristics of the arc and plasma jet were studied. On increasing the nozzle diameter, the jet power decreases by 0.5–1 kW but the stable operating region expands. In addition, this device operates stably with material loading. It is confirmed that the new type of device proposed would be very useful for various material processes.

Plasma electrode-type plasma spray gun—effect of powder loading on the behavior of plasma jet

A newly designed plasma electrode-type plasma spray gun, which can generate a high temperature and clean plasma jet and inject various materials into the center of the arc column, has been developed. In order to demonstrate the application feasibility of this new-type plasma spray gun for thermal plasma processing, the effects of powder loading on the stability and temperature of the plasma jet and on the electrode spot were studied. It was clarified that with powder loading, the plasma jet was very stable and not contaminated by electrode materials, i.e. clean, and the extent of the jet temperature decrease was a little, i.e. about 1000 K.

Wall effects on the percentage of atomic ions in a hydrogen plasma

Abstract The ratio of ion species in hydrogen plasma is calculated numerically by using a particle balance model, where the recombination factor for hydrogen atoms at the wall is treated as another plasma parameter.