Influence of Vapor-Gas Cavity on Pressure Field in Closed Discharge Chamber with Rigid Walls

The pressure field in discharge chambers of a limited volume, with rigid walls, very often has a great influence on the efficiency of technological processes; therefore, its determination is an urgent task. As a result of the electric discharge in the liquid filling of the discharge chamber, in it, a cavity with a higher compressibility is formed than the liquid in the chamber. At the discharge stage, this cavity is filled with non-ideal plasma, and after discharge, liquid vapor and gases are dissolved in it (vapor-gas cavity). Its pulsations form a pressure field in the discharge chamber. The moving boundary of the vapor-gas cavity creates great problems in calculating the pressure field in a fluid, especially after a large number of its pulsations. At present, the role of the vapor-gas cavity in the formation of a pressure field in a discharge chamber has been insufficiently studied. Its definition is the goal of this work. The study was carried out on the base of an earlier developed mathematical model of an electric discharge in water, which in this work is supplemented by relations that significantly increase the accuracy of calculating the resistance of the discharge channel and the energy released in it. It was determined that the pulsation of the vapor-gas cavity provides for the oscillation of the pressure in it in antiphase with a pressure in the liquid. The pulsations decay slowly, so a static equilibrium between the cavity and the surrounding fluid even after seven pulsations is not established in the discharge chamber. The effect of a change in the optical transparency of the plasma on the pressure in the cavity and the pressure field in the liquid, leading to a decrease in the pressure level, is determined.