EXPERIMENTAL STUDY OF A PLASMA BUBBLE CREATED BY A WIRE EXPLOSION IN WATER

International audienceAn experimental setup is developed to study the bubble dynamic created by a wire explosion in a liquid. This arrangement can be encountered in many configurations and processes and differs by the level and frequency of the applied energy and of the liquid nature. In our study the wire explosion is due to a current intensity around one thousand amps during 10ms in a water medium and a distance between the electrodes of few millimeters. By fast imaging the bubble radius is determined versus time depending on the applied energy. The results indicate that the maximum radius of the bubble versus the applied energy leads to a linear variation of 2.3 cm/kJ roughly. A modification of the Rayleigh model is proposed to consider not an empty bubble but pressure variation inside. The experimental results coupled with the Rayleigh model allow determining the maximum bubble radius, the bubble dynamic and to evaluate its mean temperature. For electrical arc energy of 846 J and an inter-electrode distance of 1 mm, the bubble presents an expansion and a collapse. A maximal radius is reached near 4 cm before 1.5 ms the end of the half current period, due to the leak of energy to feed the bubble