Experimental and Theoretical Study of a D.C. Arc in a Constant Diameter Nozzle Flow

The cold air flow field for a 1.27 cm constant diameter nozzle was determined for subsonic and transonic flow velocities. The dc arc voltage and current measurements were made for an arc gap of 5.52 cm and a current of 100A. With a channel flow model with constant arc temperature and the energy integral for the convective cooling, analytical expressions were derived for the arc radius, electric field strength, and arc voltage as functions of the cold flow properties, current, and axial distance. Calculated arc properties agree well with measured values.