Cavitation in dielectric fluid in inhomogeneous pulsed electric field

Abstract

This paper proposes a method for studying the early stages of the cavitation development in arbitrary, non-stationary conditions. This method is based on the comparison of the results of calculations in the framework of a theoretical model of the liquid dielectrics motion in a strong non-uniform electric field and experiments with controlled parameters. This approach allows us to find the critical negative pressure, at which cavitation begins to develop, and to determine the values of the constants in the classical models of cavitation

Initial stage of cavitation in liquids and its observation by Rayleigh scattering

“…where V and t are the volume and the duration of the measurement, respectively.  is the kinetic prefactor, which depends on the theoretical model used in [1][2][3][4][5][6]. For example, in [3,6], it was accepted that…”

“…The critical pressure, at which cavitation occurs can be easily estimated by equating the exponential factor in (6) . Accounting for pre-exponential factor in (6) has practically no effect for the estimation (7).…”

Pre-breakdown cavitation nanopores in the dielectric fluid in the inhomogeneous, pulsed electric fields

“…Such mechanism of а secondary cavitation ruptures generation should lead to the appearance of chains of nanopores, aligned along the electric field lines, in which the breakdown may be developed. Furthermore, this mechanism is an explosive, because the rate of cavitation ruptures generation depends strongly on the absolute value of the electrostrictive negative pressure [27], and does not depend on the rate of expansion and merging of nanopores. …”

“…Note that only the appearance of ruptures in the fluid is not sufficient for the development of * m.n.shneider@gmail.com breakdown, since at the radius of the nanopore [27], an electrostatic pressure arises in the cavitation pore, due to the distortion of its main electric field, which exceeds the Laplace pressure. In the paper [28], the estimate of the rate of the nanopores expansion is made, and it was shown that three characteristic regions are arising in the vicinity of a needle electrode.…”

On two optomechanical effects of laser-induced electrostriction in dielectric liquids

“…[3] Electrostriction plays an important role also in the manipulation of microdroplets and liquid surfaces by laser pulses [4,5]. These effects are not limited only to laser radiation, but can be achieved also by the discharge of electrodes [6,7,8].…”