Explosion of a thin metal wire with a rapidly-rising current pulse has been widely utilized as a simple and effective method to generate strong shock wave in water. In this technique, phase transition of the metal wire from liquid state to gas or plasma state during the Joule heating is known to be responsible for the generation of such a strong shock wave. Therefore, knowledge on temporal evolution of the thermodynamic state of the heated metal on the 3-dimensional (p-ρ-T) diagram is essential for understanding the origin of strong shock wave. In this work, we have developed a time-transient simulation code to analyze the wire explosion system for generating strong shock wave in water. The simulation code solves a circuit equation coupled with 1-dimensional magneto-hydrodynamic equations with the help of a wide-range equation of state for aluminum. It allows us to calculate the temporal change in thermodynamic state of the metal wire heated by pulsed electrical current. In this paper, we present the simulation results in comparison with the experiments carried out for various wire diameters and applied voltages. Also, temporal evolutions of thermodynamic properties of the heated metal wire depending on the operating parameters are discussed in terms of the strength of shock wave.
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