EXPERIMENTS ON JOULE HEATING OF SHOCK-IONIZED AIR WITH PARTICULAR EMPHASIS ON THE BOUNDARY LAYERS OF THE ELECTRODES IN THE DISCHARGE CHAMBER.
BROWN UNIV PROVIDENCE R I DIV OF ENGINEERING
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By means of selective heating of the electron gas, the conductivity of a gas can be made to exceed its equilibrium value at the same gas temperature. The method of Joule heating of the gas by a D. C. discharge was employed. All experiments were carried out with air in a 3 12 inch diameter shock tube. The gas behind the reflected shock develops an important thermal and viscous boundary layer at the walls of the electrodes, comprising the discharge chamber. The primary purpose of the experiments was to determine their effect on Joule heating of the air. The current density in the discharge chamber ranged from 300 to 7,000 Asq cm. Due to the boundary layers, a current density in excess of 600-700 Asq cm is required to efficiently heat the gas. Non-equilibrium conductivity measurements were made and compared with those computed theoretically. The distribution of voltage and current density between the electrodes was investigated. By photographing the current discharge, its stability and uniformity was determined. Author
- Plasma Physics and Magnetohydrodynamics