Shock wave generated by negative pulsed discharge in supercritical carbon dioxide

Abstract

Summary form only given. Shock waves in gases and liquids have been widely studied for several years. However, shock waves in supercritical (SC) fluids have not been adequately studied due to their special characteristics referring to both gas and liquid under high temperature and pressure. We have been considering pulsed power system as an effective way for generation of shock waves in SC phase and high-density mediums. Carbon dioxide has been adopted in this research as medium, since for CO2 we could rather easily change from the gas phase to the SC phase (Pc = 7.38 MPa, Tc = 304 K). In the present experiments, a magnetic pulse compression module was used to provide a negative pulsed voltage, which was applied to a point electrode in SCCO21. As a result, spherical shock wave was propagated from the needle tip and was observed by knife-edge Schlieren method. Meanwhile, a metal wire was used instead of knife-edge at Schlieren system's focal point to increase the sensitivity and shock waves in liquid and SC phases were observed. The generated shock waves has been analyzed and studied. The shock waves structure in high pressure carbon dioxide was discussed by comparing Schlieren method with Mach-Zehnder interferometer method results.