NUCLEATION DYNAMICS OF EXTREMELY SUPERHEATED LIQUIDS

摘要

The classical nucleation theory considers only perturbations which are small in extent but large in degree as exemplified by small vapor bubbles in a low superheated liquid. In this paper, the nucleation and the bubble dynamics in liquids which are extremely superheated up to the spinodal which is the thermodynamic boundary between the metastable and the unstable region will be discussed. A consistent description can be deduced from a variational principle. The boiling process at the spinodal exhibits an equivalence to a phase transition of second order. As important consequence the increase of the correlation length near the spinodal leads, in contrast to classical nucleation theory, to spatial increasing nuclei. The dynamics of the resulting bubbles which grow from such extended nuclei is different from the dynamics of common vapor bubbles. Even in the early stages of growing strong pressure differences occur at rigid walls.