Numerical Simulation of Phase Transition Behaviors in Metal Foils Under Low-Voltage Excitation

To investigate the dynamic behavior and plasma generation during the phase transition process of metal bridge foils under low-voltage excitation, a multiphysics coupled computational method was employed. The level set-based multiphase flow model incorporates the temperature-dependent electrical and thermodynamic properties of metallic foils to characterize the phase transition evolution in conductors. Through the integration of computational and experimental results, it was found that under low-voltage excitation, the action process of the metal foil transducers exhibits characteristics of a low-speed electrical explosion, with notable vaporization and ionization processes. The vaporization required approximately three times the duration of the liquid’s unstable development phase. The loss of conductivity began in the gas–liquid mixing phase, with conductivity dropping below 2.13e6 S/m. During evaporation, metal droplets, influenced by electromagnetic forces, vapor pressure, and their own momentum, were ejected at velocities generally exceeding 200 m/s. Because of the low induced voltage and overall low energy in the ionization process within a low-speed electrical explosion, the temperature and electron density rose slowly. Consequently, plasma was primarily generated through electric arcs formed between splattered metal droplets in high-temperature environments.