Shock Mitigation using Compressible Two-Phase Jets for Z-Pinch IFE Reactor Applications

Abstract

Compressible liquid/gas jets offer the opportunity to limit and mitigate the mechanical consequences of rapid heating/evaporation of the protective jets in a high-yield, low repetition rate Inertial Fusion Energy (IFE) system such as the Z-Pinch IFE reactor. In this investigation, experiments have been conducted to quantify the extent by which a two-phase jet can attenuate a shock wave. The experiments have been conducted using annular two-phase (water/air) jets with different velocities, void fractions, and initial shock strength. The shock is produced using an exploding wire located along the jet axis. Three different confinement geometries (i.e. boundary conditions) have been used in the experiments, namely, "unconfined" shocks, "radially-confined" shocks, and "radially-and-axially-confined" shocks. A total of 738 experiments corresponding to 39 different test conditions have been conducted. Quantitative data for the transient pressure history at the confinement wall with and without an intervening jet have been obtained; both single-phase (liquid) and two-phase (liquid-gas) jets at different velocities and void fractions have been tested. The data shows that the experiments are highly repeatable, and that two-phase jets at moderate void fractions (~1%) can attenuate a shock wave significantly more than a single-phase (liquid) jet