Transportfunktionen von Stickstoff bis 26000 °K

Abstract

TheE(I)-characteristic and a large number ofT(r, I)-distributions measured in a 5 mm ØN ₂ cascade arc at normal pressure are used to evaluate the transport properties of nitrogen up to 26,000 °K. The electrical conductivityσ(T) and from this the cross-section for atom-electron collision and the Coulomb-cross-section are determined directly from theE(I)- and severalT(r, I)-curves. For the evaluation of the thermal conductivityκ(T) three temperature regions are discerned: Up to about 10,000 °Kκ(T) is derived directly from the energy equation since here the energy transport by radiation does not play an important role. Between 10,000 and 15,000 °K the radiative energy flux for different arc currents, the thermal conductivity and from this the charge exchange cross-section are determined in a good approximation utilizing the large number of measured temperature distributions. Above 15,000 °K the already evaluated collision cross-sections are used to computeκ(T). Withκ(T) known the radial distribution of the balance between emission and absorption of radiative power per unit volume is evaluated for different arc currents. It turns out, that at the highest measured arc current, i.e. 570 A, in the axial region of the arc about 95% of the supplied energy is carried off by radiation.