Underwater electrical wire explosions under different discharge types: An experimental study with high initial energy storage

In this study, underwater electrical explosions of aluminum wires of various sizes were carried out with an initial energy storage of ∼53.5 kJ. Two piezoelectric probes were adopted to record the pressure waveforms. The experiments were divided into different discharge types, and the statistical properties of the electrical and shock-wave parameters of the different discharge types were compared. The experimental results show that there are three discharge types, called type A (breakdown type), type B (transition type), and type C (matched type). The three types differ in the resistance characteristics of the plasma channel during the plasma growth process, which are determined from the average electrical field strength and the remaining energy in the circuit at the peak voltage. Shock waves from type C discharges are more likely to exhibit a higher peak pressure, a larger impulse, and a higher energy density than the other types. However, using a matched wire that matches a specific discharge type, a high peak pressure, large impulse, and high energy density can also be achieved under type A or type B discharges. For example, the maximum peak pressures at ∼33 cm under type B and type C discharges are 38.7 and 42.4 MPa, respectively. These results provide significant guidance for load selection in underwater electrical wire explosion engineering applications.