Electric arc generators of thermal plasma (review)

Abstract. The paper describes the solutions of the building materials heat conduction problems -heating source power and size definition based on temperature measurements on a material surface and on layers, heating source characteristics and surface temperature identification by temperature measurements on a treated area. The basic problem of the building concrete block heating by mobile Gauss type thermal source are addressed. As a result there are given formulae for an estimation of the plasmatron useful power and maximal temperature on the depth z ≥ 1 mm with accuracy enough for a practical appliance. Also values of the main technological parameters during the treatment are recommended and the technology of concrete block finish is shown.

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“…[1][2][3] Most plasma devices make the low-temperature plasma by gas heating in the electric arc [1. 2].…”

Section: Introductionmentioning

confidence: 99%

Technology of treatment of building materials with the plasma torch

Galeev

Nasibullin

Sadriev

et al. 2017

J. Phys.: Conf. Ser.

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Section: Introductionmentioning

confidence: 99%

“…In addition, stricter requirements for the supply of electric power are required to stabilize the arc. In such generators to stabilize the arc and its insulation from the walls of the channel porous injection, axial flow or twist of gas are used [4,8], as well as various cavities, ledges, diaphragms, interelectrode segments are implemented [9], which complicate their design.Equipping plasma torch with gas track with divergent channel of an output electrode enables the arc burning in a laminar stream at high velocity of gas at the inlet [5,6]. Another important…”

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confidence: 99%

Generator of chemically active low-temperature plasma

Tyuftyaev

Gadzhiev

Sargsyan

et al. 2016

J. Phys.: Conf. Ser.

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Abstract.A new generator of high enthalpy (H0 > 40 kJ/g), chemically active nitrogen and air plasmas was designed and constructed. Main feature of the generator is an expanding channel of an output electrode; the generator belongs to the class of DC plasma torches with thermionic cathode with an efficiency of 80%. The generator ensures the formation of a slightly divergent plasma jet (2α = 12• ) with a diameter of D = 10-12 mm, an electric arc maximum power of 20-50 kW, plasma forming gas flow rate 1.0-2.0 g/s, and the average plasma temperature at an outlet of 8000-11000 K.Generator of low-temperature plasma (GLP) has attracted the attention of specialists in the field of gas discharge physics and low-temperature plasma, and in the field of high-temperature gas dynamics by the fact that in the discharge gap of GLP the temperature range varies from thousands to tens of thousands degrees. This provides great opportunities for research in the thermal, electrical and optical properties of gases, as well as for the research in various plasmachemical reactions [1][2][3][4].To do these researches it is necessary to have a reliable GLP, in the discharge gap of which high-enthalpy plasma stream of chemically reactive gases (nitrogen, air) is created.As such plasma source a GLP with vortex stabilization and divergent channel of an output electrode was used, which provides high flow performance and long service life of the plasma torch as well as efficient heating of the working environment and small thermal losses in the water-cooled parts of the device [5,6]. Typically, the GLP with a longitudinal gas flow are constructed with a cylindrical channel of constant cross section. The electrical discharge, features of a high-temperature gas flow, and parameters of the plasma generator with such channel are well known [7,8]. The plasma torch with a constant cross-section channel has several flaws: falling current-voltage characteristic (CVC), unsustainable modes of operation, low thermal efficiency. That is why in order to achieve the desired average plasma temperature at the outlet a lot of input power is required, which in turn affects the lifespan, energy efficiency and stability of the plasma torch. In addition, stricter requirements for the supply of electric power are required to stabilize the arc. In such generators to stabilize the arc and its insulation from the walls of the channel porous injection, axial flow or twist of gas are used [4,8], as well as various cavities, ledges, diaphragms, interelectrode segments are implemented [9], which complicate their design.Equipping plasma torch with gas track with divergent channel of an output electrode enables the arc burning in a laminar stream at high velocity of gas at the inlet [5,6]. Another important

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“…Another efficient method of processing toxic and hazardous waste is by high-temperature mineralization which involves the use of low-temperature plasma as an additional source of thermal energy [1][2][3][4][5][6]. Almost all of the plasma facilities for waste processing involve the use of high-current arc discharges or electric-arc plasma generators, because this is the only way of ensuring the desired energy density with a fairly high power [7][8][9][10][11]. In the discharge chamber of a plasma generator, the electrical energy input to the arc is converted by way of heat transfer to the internal energy of working gas.…”

Section: Introductionmentioning

confidence: 99%