Heterogeneous bubble nucleation on heated surface from insoluble gas

摘要

Based on thermodynamic analysis, a model of heterogeneous bubble nucleation on a heated surface from an insoluble gas bubble is developed. Line tension is included in the model, which not only contributes to the change of thermodynamic potential (Gibbs free energy) during bubble formation but accounts for the variation of contact angle during nucleation process. The dependence of surface tension on temperature is also considered. The change of Gibbs free energy during bubble formation, which can be used to evaluate the stability of bubbles, is calculated. In the process of bubble growth, two stable or metastable bubble radii are found before and after the critical radius of bubble formation is reached. In addition, a parametric study is conducted to investigate the influence of the initial bubble size, line tension, wall temperature, wall temperature gradient and surface tension on the nucleation process. The present study provides a basis for heterogeneous nucleation from a pre-existing nucleus.