17:00 〜 17:15
▲ [21p-W611-7] Analysis of microplasma discharge process in sea water
キーワード：microplasma,sea water
This paper proposes a micro-gap plasma discharge in a highly conducive seawater and reports on discharge characteristics under variable discharge parameters.
For the experiments, two types of sea water were used. Artificial sea water 10 (10ASW) and the natural deep sea water (DSW).
A needle(Pd)-to-plane(Pt) electrode system was sunk into sea water in a quartz cuvette. The needle was 50 μm in tip radius. The gap between electrodes was ranged from 10 to 40 μm.
An impulse generator circuit consisting of a capacitor and an inductor with an MOSFET switch was used. Inductance and capacitance were ranged in 10-150 μH and 7-220 nF, respectively. The capacitor was charged to 500-1000V. Each discharge was operated by one shot. The voltage and current waveforms were stored in a digital oscilloscope (IWATSU-LeCroy AP015). The maximum voltage and current for this scheme were 1kV and 30A respectively.
It has been confirmed that, using the micro-gap configuration, spark discharges were ignited at the conventional breakdown voltages 130-400V even in the conductive sea water. It was found that small bubbles appear around electrodes before plasma ignition. From the appearance of bubbles, it can be expected that the discharge initiates in bubbles.
The charging voltage of capacitor, the breakdown voltage, the energy consumption for breakdown, the duration of discharge were investigated with variation of the gap length and circuit parameters.
For the experiments, two types of sea water were used. Artificial sea water 10 (10ASW) and the natural deep sea water (DSW).
A needle(Pd)-to-plane(Pt) electrode system was sunk into sea water in a quartz cuvette. The needle was 50 μm in tip radius. The gap between electrodes was ranged from 10 to 40 μm.
An impulse generator circuit consisting of a capacitor and an inductor with an MOSFET switch was used. Inductance and capacitance were ranged in 10-150 μH and 7-220 nF, respectively. The capacitor was charged to 500-1000V. Each discharge was operated by one shot. The voltage and current waveforms were stored in a digital oscilloscope (IWATSU-LeCroy AP015). The maximum voltage and current for this scheme were 1kV and 30A respectively.
It has been confirmed that, using the micro-gap configuration, spark discharges were ignited at the conventional breakdown voltages 130-400V even in the conductive sea water. It was found that small bubbles appear around electrodes before plasma ignition. From the appearance of bubbles, it can be expected that the discharge initiates in bubbles.
The charging voltage of capacitor, the breakdown voltage, the energy consumption for breakdown, the duration of discharge were investigated with variation of the gap length and circuit parameters.