Gas-vapor bubble nucleation--a unified approach.

In a solution which is saturated with gas near the superheat limit, one might expect a bubble formed from both dissolved gas and vapor molecules to appear. The integration of the surface-energy concepts, that are postulated on completely different physical bases for gas and vapor bubble formation is a major issue. In this paper, we reformulate gas and vapor bubble nucleation by a scaling transformation, which turns the surface energy for the bubble formation from both dissolved gases and vapor molecules to the translational energy of a molecule, (3/2)kBT. With this unified approach, one could estimate the dissolved gas effect on the superheat limit of the liquid. The driving force and the molecular volume are important quantities for determining the number of gas and vapor molecules composed of a critical cluster. This approach, of course, can predict pure gas bubble formation, as well as pure vapor bubble formation, as limiting cases. Also, this approach makes it possible to find that the possible occurrence of gas bubble nucleation by dissolved gases prevents measuring the theoretical superheat limit of water at atmospheric pressure, 300 degrees C.