National Repository of Grey Literature 3 records found  Search took 0.00 seconds. 
Electric probe measurements in the anode area of a DC arc plasma torch at low pressure
Ondáč, Peter ; Mašláni, Alan ; Hrabovský, Milan
We measured radial profiles of the electric field, plasma electrical potential and electron temperature in the hot anode area of a hybrid water-argon DC arc plasma torch with an external anode. The measurements were made under different values of the ambient pressure, during the restrike mode with a constricted anode arc attachment or during a supersonic mode with a diffuse anode arc attachment. The results provide first experimental data on plasma electrical potential in that anode area.
Material design problems of plasma-chemical reactors for disposal perfluorinated compounds
Brožek, Vlastimil ; Březina, Václav ; Mastný, L. ; Kubatík, Tomáš František ; Živný, Oldřich
Reduction of perfluorinated gases emissions from semiconductor industry has recently introduced a serious problem from both technological and economic side. With respect to chemistry of the decomposition reactions the most effective abatement techniques developed up to now consists in the interaction of those gaseous pollutants with several types of plasmas. In the framework of Czech-Taiwanese bilateral project No. 17-10246J 'Decomposition of Perfluorinated Compounds and Fluorinated Ozone Depleting Substances' a new plasmochemical reactor design is to be solved. In this reactor the plasma abatement process consisting of interaction of the plasma generated by unique watter stabilized H-WSP plasma torch at temperatures ranging\nfrom 2000 K up to 25,000 K with the treated gases will be carried out. However, the main product generated in the reactor during the steam plasma abatement process is hydrogen fluoride which causes corrosion of almost every construction material. The aim pursued by the work presented is to search for the materials resistant to exposition of HF even at high temperatures. To investigate corrosion resistance of construction materials with thermal stability within temperature interval 2700-3000 °C titan nitride, boron nitride, and silicon carbide have been selected. The samples of those materials have been prepared by spark plasma sintering method and exposed to concentrated solution of hydrofluoric acid for which corrosion rates have been measured
Measuring of Mean Plasma Electrical Conductivity in Anode Area of Plasma Torches with an External Anode
Ondáč, Peter ; Mašláni, Alan ; Hrabovský, Milan
We developed a non-intrusive direct procedure of measuring an average electrical conductivity of a plasma volume in hot anode areas of those plasma torches. For our measurements, we used a high-speed camera, a high-voltage probe, and a hybrid water–argon plasma torch. The measurements were made for various values of ambient pressure, arc electric current, and argon flow rate. The measured plasma conductivity is in agreement with a model, camera observations and indirectly also with spectroscopy measurements. The procedure provides missing experimental data on the average plasma electrical conductivity and estimates average plasma temperature in the anode areas. The procedure can be theoretically used in every plasma torch where the anode arc attachment movement can be observed during a restrike process\n

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