REIGNITION OF FREELY RECOVERING SPARK CHANNELS IN HYDROGEN

Abstract

The paper describes an experimental technique and apparatus for the measurement of spark gap reignition in freely recovering spark channels in hydrogen. A unidirectional 235-ka current pulse produces the initial discharge while subsequent reignition is effected by a voltage generator whose output approximates a step-function over 50 μsec. Recovery characteristics are given for 16-mm-diameter tungsten rod electrodes in hydrogen at pressures ranging from 200 to 760 mm Hg, for 4-mm-diameter tungsten rods, and for 16- and 76-mm-diameter copper electrodes at 760 mm Hg. Gap length was varied from 1 to 5 mm. Study of the parameters shows that electrode size has the most pronounced effect on the recovery process.The deionization and recovery mechanisms are predicted theoretically and verified during the final recovery period where reignition by spark breakdown is observed. Gas temperatures derived from the recovery results are in good agreement with measured values.