Database system of thermodynamic properties of individual substances at high temperatures

Abstract

Theoretical starting points and methods leading to the creation of a consistent database of thermodynamic properties of individual substances are given. The database is easy to modify and update. An exact definition of the concept consistent is given after all the relations and connections have been given. The proposed general methods are realized using computer programs and the species file, in which the thermodynamic properties of 326 gaseous and 34 condensed substances are stored that were prepared from a set of elements . Together with other files and programs the species file forms the database system , which is described in detail below, and stored as from the date of publication of this paper at the address http://www.feec.vutbr.cz/~coufal/.

On the Selection of Integration Intervals for the Calculation of Mean Absorption Coefficients

“…First we calculated the plasma composition of air at 20 kK and 1 bar, according to [16] with species standard thermodynamic functions taken over from [17]. The spectral absorption coefficient was then calculated with the approach given by Aubrecht et al [18] and is shown in Fig.…”

P1-approximation for radiative transfer: application to SF6 + Cu arc plasmas

“…In the mixture of SF 6 and Cu plasma, we assume the following species: SF 6 molecules, S, F, Cu neutral atoms, S + , S +2 , S +3 , F + , F +2 , Cu + ions and free electrons. Molecular products of SF 6 dissociation were neglected due to the lack of data for their absorption coefficients.…”

“…We have only taken into account SF 6 molecules with their experimentally measured absorption cross sections [5]. The equilibrium composition of the plasma was taken from [6]. In Fig.…”

“…In the mid and high voltage region, SF 6 self-blast circuit breakers are widely used. Radiative heat transfer influences very much the physical processes occurring in the arc plasmas.…”

“…Recently, we have used an approximate method of partial characteristics to evaluate the radiation properties of SF 6 arc plasmas with various admixtures of Cu [1,2]. The method of partial characteristics is generally accepted as a very good mathematical tool for prediction of radiation transfer in the arc plasmas.…”