Freezing of Water Droplets in Equilibrium with Different Gases

Abstract

Water droplets in thermal equilibrium with gases of different solubilities were frozen at temperatures between ?4 and ?14C, in order to observe the influence of the volume of dissolved gas on the shattering of the droplet. In air, which has a low solubility in water, no shattering was produced. In methane with a slightly higher solubility, 5% of the droplets shattered. In mixtures of carbon dioxide and air, the frequency of shattering is a function of the temperature and the concentration of carbon dioxide, attaining under the most favorable conditions a value of 40%. However, a large volume of gas is not a sufficient condition to produce shattering. In acetylene, which has nearly the same solubility as carbon dioxide, and in sulfur dioxide, the solubility of which is more than one order higher, shattering was not observed, either in the pure gas or in mixtures with air. When the released gas is readily dissolved in the remaining solution (as for droplets in acetylene or low concentrations of sulfur dioxide) or the gas is separated in a solid phase as a hydrate (as for droplets in high concentrations of sulfur dioxide), the gas does not contribute to an increase of the internal pressure, thus eliminating the possibility of shattering.