Physical mechanisms controlling a vapor bubble collapse and formation of a liquid jet during a laser-induced subcooled boiling near the end face of a thin waveguide

Abstract

Laser-induced subcooled boiling near the tip of thin waveguide immersed in a liquid which temperature is less than the saturation temperature (subcooled liquid) can produce intensive liquid jets finding promising applications in medicine. Individual act of the boiling process consists of successive stages of the bubble inflation, bubble collapse and formation of the jet. In this paper we investigate the contribution of different physical mechanisms to the characteristics of these stages. Simplified mathematical model introducing evaporation and condensation processes in the fully controlled manner allows manipulation of these processes by varying model parameters. Depending on the evaporation intensity or disequilibrity of the bubble inflation stage three regimes of laser-induced subcooled boiling can be distinguished, that are the pressure driven regime, transition regime and condensation driven regime. Distinctive features of these regimes are discussed and ranges of evaporation intensity and disequilibrity index typical for each regime are determined. The validity of incompressible gas assumption for description of different regimes is estimated.