水中放電成形法における放電特性と衝撃圧力波

Abstract

The electrohydraulic forming method makes use of energy generated by impulsive high current discharge across electrodes which are usually bridged by an initiating wire.In this investigation, the wave forms of this discharging current and discharging voltage across electrodes were measured under various spark conditions. The electrical characteristics of the spark gap and the behaviour of exploding wires were made clear based on the wave forms obtained.In the wave forms of current and voltage, discontinuity points appeared as the phase of exploding wire changed from a solid state to a liquid phase and to a vaper phase. The time when the discontinuity points appeared was closely affected by the spark conditions.The value and the profile of the pressure wave generated by an exploding wire across the spark channel in water were calculated theoretically. These results were in good agreement with the experiments and could explain the characteristics of the pressure wave.