National Repository of Grey Literature 25 records found  previous11 - 20next  jump to record: Search took 0.01 seconds. 
Experimental study of of time development of pulsatile jets using classical PIV method
Kopecký, V. ; Kotek, M. ; Pírková, L. ; Jašíková, D. ; Trávníček, Zdeněk ; Hlína, Jan
This paper describes a quantitative visualization of pulsatile flow fields using classical PIV method. A synchronization of PIV measurement with the control signal allows to acquire flow fields maps with time steps less than 1ms. The results are presented for jets from weaving nozzles, for controlled jets, and for plasma arks for electrostatic spinning.
Nové metody záznamu chování volného proudu plazmatu užívající vláknovou optiku
Šonský, Jiří ; Hlína, Jan ; Něnička, Václav
The fibre optics coupling to photodiodes used in plasma jets optical radiation recording enables us to increase the channel count and to add flexibility to an experimental layout for multi-directional observations. These improvements give us opportunity of more detailed and important plasma jets behaviour analysis - reconstruction of luminosity fields (close to relative value of enthalpy) in planes perpendicular to a plasma jet axis, velocities and tracking of plasma jet axis movements. Details of experimental hardware and layount will be also shortly presented.
Větvení obloukového kanálu ve vnějším magnetickém poli
Mrázek, Josef ; Hlína, Jan
An electric arc burning in mercury vapours exposed to external magnetic field changes its discharge path into a helix according to the Thomson principle of energy minimization. The voltage between the adjacent turns of the helix curvature may result in the critical electric field strenght in the vicinity of the arc channel, that leads to the branching and formation of a new discharge path acting as a turn-to-turn short. We have been interested in the electric field profile and surrounding parameters at the moment of branching, the speed of a new channel warming, temporal evolution of the restoration of a regular spiral channel, development of the arc current and distribution of the voltage between the series resistor and arc channel during the breakdown.
Měření rozdělení teplot ve volném proudu plazmatu CCD kamerou
Hlína, Jan ; Šlechta, Jiří ; Šonský, Jiří ; Gleizes, A. ; Gonzales, J. J. ; Cressault, Y.
The method is based on the application of a fast shutter colour CCD camera thet is able to provide simultaneous images of a plasma jet in different spectral regions. Both the experimental and theoretical results have shown that it is possible to apply the method to measurements of temperature fields in argon thermal plasma jets in the range 8000 - 11000 K. The ratio of red to blue components is preferable due to the steepest dependence on temperature.
Diagnostics of Breakdown in Electric Arc Exposed to External Magnetic Field
Hlína, Jan ; Šonský, Jiří
An arc in external magnetic field acquires a helical shape and when the magnetic field exceeds a critical value the arc starts to oscillate. The oscillations may lead to many types of shortenings (breakdowns) between the adjacent windings of the arc path. We have investigated experimentally the steepness of the voltage fall reflecting the breakdown and the influence of mean arc voltage and electrode polarity on this characteristic.
Investigations of the Arc Voltage and Length Modulation in External Magnetic Field
Hlína, Jan ; Něnička, Václav
The experimental investigations deal with an arc burning in mercury vapours which was exposed to an axial magnetic field, causing arc oscillations mostly of a rotary character.

National Repository of Grey Literature : 25 records found   previous11 - 20next  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.