On heating gases with non-constricted electrical discharges

Abstract

This paper is concerned with non-constricted discharge heaters. The discharges in these devices, although within an enclosure, are limited in size by heat transfer to the flowing gas, rather than to the walls as in the case of constricted discharges. The advantages of heaters of this type are discussed and a number of examples of their uses cited. The first part is concerned with discharges in the absence of magnetic fields. A method of calculating the fraction of the gas flow directly heated by the discharge and the mean temperature that it attains is presented in terms of parameters that are easily measured experimentally. The second part deals with heaters based on magnetically rotated arcs and the conditions necessary for the uniform heating of the emerging gas are considered. A method of estimating whether these conditions are fulfilled in any given circumstances from measurements of the rotational frequency and visible diameter of the arc is presented.