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Arc–Anode Attachment Area in DC Arc Plasma Torch at Low Pressure
Ondáč, Peter ; Mašláni, Alan ; Hrabovský, Milan
Studying the processes in the anode attachment area of a DC arc plasma torch helps to extend the lifetime of the anode, stabilize the plasma flow for plasma spraying and better understand the movement of the anode attachment. In this work, such processes were studied at low pressure, by a non-disturbing method, using a high-speed camera and a high voltage probe. We also found pressure ranges, in which the following transitions were observed: the constricted/diffuse anode attachment, and subsonic/supersonic plasma jet\n
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Investigation of Anode Attachment Area in Water/Argon Stabilized Plasma Arc
Ondáč, Peter ; Mašláni, Alan ; Hrabovský, Milan
Arc-anode attachment in a DC plasma arc stabilized by water vortex and argon, influences power distribution in the plasma, lifetime of the anode and also flow structure of the plasma jet. A movement of the attachment and the surrounding plasma has been directly observed by using a high-speed camera (max. 1,080,000 fps). The observations were compared with cathode–anode voltage measurements (sample rate 80 MHz). More than one attachment was observed in one frame with exposure time 0.25 μs or 0.29 μs. We have directly measured average velocities of the attachments and hydrodynamic waves above them, as well as the characteristic dwell times and dwell frequencies of the attachments
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Electric Probe Diagnostic of Supersonic Thermal Plasma Jet
Hurba, Oleksiy ; Hrabovský, Milan
This paper describes how electric probes can be used as relatively simple and efficient tool for investigation of structure of flow field in thermal plasma jet at the low pressure. A boundary of plasma jet between nozzle of plasma torch and ambient air was investigated by means of array of moving electric probes. Were defined boundaries of the conducting region and their change with pressure change
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Properties of Novel Hybrid Water-Gas DC Arc Plasma Torch
Chráska, Tomáš ; Hrabovský, Milan ; Glanc, Aleš ; Mušálek, Radek ; Medřický, Jan
A new type of plasma torch with combined stabilization of electric arc by water vortex and gas flow is presented. This hybrid water/gas stabilization offers the possibility of adjusting plasma jet parameters within a wide range from high-enthalpy low-density plasmas typical for liquid stabilized torches to lower enthalpy higher density plasmas generated in gas stabilized torches. Moreover, gas flow in the cathode part protects a cathode tip and thus a consumable graphite cathode used in water-only stabilized plasma torches could be replaced by a fixed tungsten cathode. Examples of hybrid WSP torch utilization for high temperature application are given.
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Thermal plasma gasification of organic waste and biomass
Hrabovský, Milan
The paper presents description of thermal plasma gasification processes. Analysis of energy balances of plasma gasification is presented, kinetics of the gasification process is discussed and relations between particle size, reaction temperature and gasification rate are analyzed. Examples of results of gasification of biomass and pyrolysis oil from used tires are given. Syngas with high heating value, high hydrogen content and low tar contamination is produced by plasma gasification.
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