The Energy Transport, Including Emission and Absorption, in N2-Arcs of Different Radii

Steady, motionless cascaded N2-arcs with tube diameters of 2, 3, and 5 mm are investigated at atmospheric pressure to gain insight into the radiative energy transport for temperatures up to 27,000 K. From the electrical characteristics, the total emitted radiation, and the temperature distributions, the electrical conductivity and the transparent emission are evaluated. It is shown that transparent emission can be neglected in the energy transport of nitrogen. The thermal conductivity and the radiative balance as the difference between total emission and absorption per unit volume are determined by introducing the concept of a zero radius arc. Extrapolation to the zero radius arc also permits the determination of the total emission alone. The emission and reabsorption of radiation plays a decisive role in the energy transport for temperatures above 13,000 K.