Supersonic water jets driven by exploding conical wire arrays and their impact on aluminum targets

Abstract

This work investigates the formation of supersonic water jets produced by exploding conical wire arrays and their impact on aluminum targets of different thicknesses. Experiments are performed using the pulsed power driver at beamline ID19 of the European Synchrotron Radiation Facility (ESRF), with the wire arrays driven by a 95 kA electrical discharge with a current rise time of ∼550 ns. Jet formation is diagnosed using multi-frame enhanced phase-contrast x-ray radiography at a pulse repetition rate of 5.68 MHz. Jet velocities in the range of 1450 − 1820 m/s are achieved, and the radiographs suggest a strongly density-depleted, possibly hollow jet core surrounded near its base by denser liquid set into motion during jet formation. For a jet impacting a thick aluminum target, radiographs show a high-density stagnation region at the impact position and radial water splashing caused by redirection of the incoming liquid flow along the target surface, followed by atomization of the spreading liquid. Axisymmetric compressible multiphase Navier–Stokes simulations estimate a peak impact pressure of ∼1.4 GPa, associated with initial water-hammer loading. In separate jet penetration experiments on thin aluminum foils, the material deformation rate decreases with increasing foil thickness, and foil perforation is observed up to a target thickness of 0.3 mm, consistent with analytical estimates based on a shear-failure criterion.