INVESTIGATION OF ELECTRIC ARC INTERACTION WITH AERODYNAMIC AND MAGNETIC FIELDS.

An experimental study of a balanced electric arc of 200 to 400 amperes in an atmospheric pressure cross-flow air stream of velocities up to 60 ft/sec and transverse magnetic field strengths up to 50 gauss was made. An open-jet type facility permitted the use of diagnostic techniques in the arc wake region. The arc's significant dimension transverse and parallel to the flow was measured. This dimension increased transverse to the flow and decreased parallel to the flow as the transverse blowing velocity was increased. Velocity profiles, energy flux distributions, relative turbulence levels and frequency measurements were obtained in the arc wake using miniaturized probe techniques. Flow visualization studies were performed using micron-sized particles. The input and output arc power distribution was obtained. The energy convectively transferred to the arc wake was equal to the additional electrical energy input required to maintain the arc in the presence of the transverse blowing. A drag coefficient for the arc, analogous to that of a solid cylinder subjected to a cross-flow, was defined and measured to have values between 0.7 and 1.2. Comparisons between the wake of an arc and that of a heated solid cylinder indicated similarity in vortex shedding frequency and convective heat transfer. (Author)