On the possibility of homogeneous nucleation of water droplets and/or ice crystals during the bounces of a cavitation bubble

TL;DR

This paper investigates the potential for homogeneous nucleation of water droplets and ice crystals within cavitation bubbles during their rebound phases, using numerical simulations and nucleation kinetics to explore phase transitions.

Contribution

It introduces a detailed analysis of bubble dynamics and phase transitions, proposing a mechanism for ice nucleation during cavitation that has not been thoroughly examined before.

Findings

Bubble core temperature drops below 0°C during rebounds

Homogeneous nucleation of droplets is possible in bubble core

Nucleated clusters could trigger ice formation in surrounding water

Abstract

Acoustic cavitation is known to trigger ice nucleation in supercooled water. Several competing and still debatable mechanisms have been proposed in the literature and are related to the pressure field in the vicinity of the bubble at the end of its collapse. Numerical simulations of the bubble dynamics show that during the bubble expansions in the bounces following the main collapse, the bubble core temperature reaches values far below 0 {\deg}C for time periods of about 500 ns. The water vapour present in the bubble during these time intervals explores the liquid and the solid region of the phase diagrams before going back to the vapour region. On the base of approximate nucleation kinetics calculations, we examine to what extent liquid droplets could nucleate homogenously in the bubble core during these excursions. We also discuss the possibility that the nucleated clusters reach the bubble wall and trigger ice nucleation in the surrounding liquid if the latter is supercooled.