Effect of Pressure on Discharge Initiation and Chemical Reaction in a Liquid-Phase Electrical Discharge Reactor

The effect of pressure on liquid-phase electrical discharges was investigated by using a stainless steel high-pressure reactor combined with a high-voltage pulse forming network. The initiation breakdown voltage was obtained under various pressures up to 1380 kPa (200 lb/in² ). The discharge characteristics including current and voltage waveforms as well as power per pulse were determined. The effect of pressure on streamer chemical reactions was also investigated by measuring the formation rate of hydrogen peroxide (H₂O₂) in the solution. Experimental results showed that the initiation voltage is linearly dependent on pressure. The initiation voltage and power were correlated to the increase of heat requirement to vaporize liquid water with increasing pressure. On the other hand, when the input voltage exceeds the initiation voltage such that a stable discharge can be formed, the discharge characteristics are not affected by pressure. Hydrogen peroxide generation was also not affected by external pressure for conditions with stable discharge. To explain the aforementioned results, the bubble theory of liquid-phase breakdown initiation is discussed.