Metallic jet production using pulsed electrical discharges in water

Capacitor-bank driven pulsed electrical discharges in water can create high pressures, of the order of several tens of kilobars. Such pressures have industrial applications, such as in rock fragmentation. We report, for the first time, the use of such discharges to accelerate thin metallic liners to high velocities. The liners turn into high-velocity jets, which can perforate metal sheets. These experiments make use of a 15 kV, 60 kJ capacitor bank. The bank delivers energy to the load through a coaxial cable. The load is a fluid-filled cavity consisting of a right-circular cylinder, one end of which is heavily tamped. The other end is bounded by a conical copper liner. The cavity is filled with a viscous fluid. Discharge of the capacitor bank dumps energy in a small region of the fluid, producing a high pressure "hot zone". The resulting shock/pressure waves produce liner collapse and acceleration, leading to a high-velocity jet. Approximate measurements indicate that the velocity lies in the range 1.4-1.6 km/sec. We have studied the performance of these jets for metal plate perforation. Jets produced by a Cu liner can perforate up to 5 mm of Al sheet. The design and performance of this system is discussed.