Radiation Heat Transfer in Thermal Argon Plasma with Iron Vapors

The objective of this paper consists of approximate calculations of thermal radiation heat transfer in ar-gon arc plasma with admixtures of iron vapors. As a mathematical tool, the P1-approximation has been used. To simplify the calculations, the frequency dependence of absorption coefficients has been handled by means of Planck and Rosseland averaging methods. Calculations has been performed for isothermal cylindrical plasma of various radii (0.01 to 10 cm) in temperature range 1 000 – 30 000 K

Optimization of 3-band Mean Absorption Coefficients

In this paper we present a process for mean absorption coefficient optimal band selection applied to the 3-band model of radiation in an air electrical arc. For fixed temperature, the divergence of radiation flux in an infinite cylindrical plasma column is calculated using spectrally resolved absorption coefficient and serves as a reference value. Optimization process is used to properly select the bands of 3-band mean absorption approximation using both unmodified and limited Planck mean absorption coefficient. The ac-curacy of aforementioned two approximation methods is evaluated

Equilibrum Composition of Thermal Plasma with Copper and Chromium Vapours Admixtures

Thermal plasma of electric arc is widely used in various technological applications: welding, cutting, lamps, spraying, protection of electrical installations, etc. Process efficiency is defined by different parameters that determine arc operation and influence the energy transfer within the medium. All energy exchanges depend on the medium, which is modified by the presence of the arc and more particularly by the appearance of new species from contact erosion. Sintered Cu-Cr composites are widely used as electrical contacts for vacuum circuit breakers. These materials take advantage of the high thermal and electrical conductivity of Cu and of the refractory and oxygen getter properties of reinforcing Cr particles. The aim of this paper is to give results of the calculation of the equilibrium composition of argon and air plasma with various admixtures of Cu and Cr

Modelling of Radiative Transfer in Air Arc Plasma

The objective of this work is to compare the accuracy of several approximate models of radiative properties for the prediction of radiative transfer in air arc plasma at the temperatures in the range of 300 - 25 000 K and the pressure of 0.1 MPa. Calculated absorption coefficients are used to generate the parameters of different models. The radiative transfer inside the cylindrically symmetrical air plasma with prescribed temperature profile was studied. The equation of radiative transfer was solved using the P1 and SP3 approximations, calculated radiative source term in the energy equation (net emission) was compared with results obtained by spectral integration

Thermal Plasma of Electric Arc Discharge Between Cu-Cr Composite Electrodes

This work deals with investigations of model plasma source realised as electric arc discharge in gas atmosphere between Cu-Cr composite electrodes. Radial distributions of temperature and electron density in arc plasma column were studied by optical emission spectroscopy. The content of electrode metals' vapours in discharge was calculated on the base of experimentally obtained plasma parameters as initial data. So, in this way the erosion properties of such composition can be determined

Peculiarities of interaction of Cu-W composite materials with thermal arc discharge plasma

This work is a part of acomplex investigation of the interaction of Cu-W composite materials with thermal electric arc discharge plasma. The plasma of 3.5 A DC arc discharge between novel Cu-W composite materials, fabricated by shock pressing technology at the temperature of 750°C, was studied at this stage. Spectra of such plasma emission were registered and treated to determine the radial distributions of plasma temperature in three different cross-sections of the plasma channel, namely in near-cathode, near-anode and middle cross-sections.Описано частину комплексного дослідження взаємодії Cu-W композитних матеріалів з термічною плазмою електродугового розряду. На цьому етапі роботи досліджувалась плазма дугового розряду постійного струму 3,5 А між новітніми композитними матеріалами Cu-W, які виготовлені за технологією ударного пресування при температурі 750°C. Зареєстровано та оброблено спектри випромінювання такої плазми з метою визначення радіального розподілу температури в трьох різних поперечних перерізах плазмового каналу, а саме в прикатодному, прианодному та середньому перерізах