Spectroscopic studies of back-discharge
ABSTRACT Different forms of low current back-discharge in air at atmospheric pressure with fly ash used as a dielectric barrier are
discussed in the paper. The discharge was characterized in terms of optical emission spectra and current-voltage characteristics.
The discharge emission spectra in the wavelength range of 200÷540 nm have been measured to investigate behavior of the species
present in the fly ash when back-discharge is initiated. In normal conditions the emission spectra are dominated by atmospheric
components (molecular nitrogen, atomic oxygen and nitrogen) but atomic lines due to chemical composition of the fly ash were
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ABSTRACT: The mode change and flashover voltage of back discharge under different gaseous conditions were studied with special attention to the effects of dust layer thickness and alkaline components contained in dust. It was found that back discharge took either a streamer or a steady-glow mode depending upon the gas mean-free-path. These modes have their own characteristics flashover voltage as a function of gas mean-free-path, where its value for the former mode is much lower than that for the latter. The thickness of the dust layer and the existence of the alkaline components also govern the initiation of a streamer so that the flashover voltage is affected greatly by these factors.Journal of Electrostatics - J ELECTROSTAT. 01/1978; 4(3):215-231.
Article: Light measurement of back discharge[show abstract] [hide abstract]
ABSTRACT: Light measurements of back discharge are made under negative d.c. high voltage and negative pulse high voltage application, with the aid of a photomultiplier tube and an image convertor camera connected to an image intensifier. The light signal of back discharge in the mixed streamer mode indicates that it consists of two parts, the primary light wave rising very rapidly, and the secondary light wave rising more slowly. The former proceeds into space while the latter proceeds along the layer surface. In the space streamer mode, the primary light wave is dominant and the secondary light wave is very weak. When a sufficiently high pulse voltage is applied under lower pressure, back discharge is triggered by free electrons supplied from the needle electrode. As the pressure is increased, an abrupt change in the triggering carries occurs from electrons to negative ions.Journal of Electrostatics - J ELECTROSTAT. 01/1977; 2(4):375-396.
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ABSTRACT: Modes of back discharge occuring in the electrostatic precipitator were studied using, instead of a dust layer, the model samples of glass and mica plates with a pinhole, and tissue papers. It was confirmed that back discharge started to occur when the apparent field strength in the sample layers exceeded its breakdown field strength. Back discharge became a streamer corona under atmospheric conditions. It could be classified into a space streamer mode, a surface streamer mode and a mixed streamer mode, depending upon the field distribution around the breakdown point in the sample layers. The first and the third modes occurred when the field strength in the air gap, Ea, exceeded about 5 kV/cm, and positive ions were generated in the whole gas space. The second mode appeared when Ea was lower than about 5 kV/cm, and ion generation was limited to the near surface region. Among the factors affecting the back discharge, dust resistivity was the most important. For low dust resistivity, space streamers tended to develop from the breakdown points when the applied voltage was raised. For high dust resistivity, on the other hand, the number of breakdown points increased, and surface discharge was pronounced. A remarkable difference in modes was observed when using positive corona. Neither space streamer nor surface discharge occurred and the flashover voltage was higher than that with negative corona.Journal of Electrostatics - J ELECTROSTAT. 01/1977; 4(1):35-52.