Study On Influence Of Shock Waves Induced By Underwater Pulse Current Discharges

The shock wave generated by high-voltage pulse discharges in liquid has been widely used in industrial applications.In this paper,an integrated experimental platform of underwater pulse discharges is established,a needle-plate electrodes system with the adjustable gap distance is used.The influence of voltage polarity on the process,morphology and physical characteristics of streamer development are discussed,based on the analysis of energy transfer process,the influence of voltage polarity on the shock intensity is studied.The results show that for the subsonic streamer,the use of negative polarity voltage can significantly improve the energy conversion efficiency of the shock wave.For the positive polarity,the supersonic streamer mode can significantly reduce the energy loss of the prebreakdown process,and obtain a higher intensity of shock wave.Using the negative polarity voltage,or controlling the voltage of the positive polarity to make streamers develop in the supersonic streamer mode,can significantly improve the intensity of the shock wave.The influence of the gap distance on the shock wave characteristics is analyzed,the results show that positive and negative polarity breakdown voltages show different trends with gap distance,and shock intensity increases gradually with increasing gap distance.In the deep well and deep sea,the hydrostatic pressure has an influence on the characteristics of the shock waves induced by underwater electrical discharges.In this paper,the experimental platform of underwater electrical discharge is established.The variation of pre-breakdown time delay with hydrostatic pressure and breakdown mode,and the energy loss in the pre-breakdown process are studied.The influence of hydrostatic pressure on the propagation and expansion of shock waves are deduced,and the relationship between shock wave intensity and hydrostatic pressure is established,which can provide theoretical guidance for the industrial applications.The results show that regulating the voltage of the positive pin-plate electrode,and making it work in the supersonic streamer breakdown mode,and maintaining a high initial shock energy,which are more conducive to improving the energy conversion efficiency of shock wave in generation and propagation process.