Molecular dynamics study of liquid–vapor transition in underwater electrical wire explosion

During underwater electrical wire explosion, liquid–vapor transitions are crucial to the energy deposition and the generation of shock waves. To explore the characteristics of liquid–vapor transition during electrical explosions in water, a large-scale molecular simulation method was designed. The modeling scales experimental exploding wires to nano-size and then tracks the motion of each atom. The surrounding water medium was simplified as an expanding wall, whose velocity was determined by experimental steak images. Using this model, the phase transition processes at different energy deposition rates were compared. The results show that high energy deposition rates can make the discontinuous liquid–vapor phase transition disappear, forming an axially uniform vapor column, while slow energy injection will change the exploding wire into a foamlike liquid–vapor mixture at a subcritical temperature. The different shapes of wire–water interfaces in the experimental shadowgraphs can be explained by these features of liquid–vapor transition.